Yeah, no. Abortion is a litmus test for most of them; if Trump supported that they’d turn on him in a second. Trump was able to get away with outrageous crap, but it was all outrageous crap his base either supported or didn’t care about.
You’d have two big limitations as Trump: what the base would accept, and what the Republicans in Congress would support. In the original timeline they couldn’t even agree to repeal the ACA, which was something they were supposedly all in favour of.
Red_wiggler has my answer.
But seriously, what had people on board with Trump was “pwning the libs”, and so everything I’d do has to be phrased in that context. The speeches are formulaic.
“I’m the best at [topic]. I know a lot about [topic]. The dems don’t know anything and they’re trying to steal my [topic]. That thing they did, that doesn’t belong to [topic] at all. My thing? It’s the best, most beautiful thing ever. We’ll make America Great again, just you watch.”
Anybody noting how I’m acting differently will get brushed off as hating America or being jealous of how great of a Preznit I am. Anybody opposing my plan will have their credentials questioned and will also be assigned a juvenile, insulting nickname.
Now, while I’m talking all that talk and riling up my base, I’d just go ahead and enact a moderate, reasonable policy, and then aggressively deny everything as some kind of Democratic whinining because they hated how awesome I was. Let’s go build some yuge, beautiful roads. Let’s fix American’s bridges, because they’re the best in the world. The Democrats hate our big, beautiful NATO alliance. They resent how much awesome trade we’re doing. Trade wars are easy to win? Nah bro, TRADE is easy to win. Democrats want you all on welfare and I’m making all these awesome jobs. Wait’ll you see my Trumpcare, it’ll be the best ever. (It’s Obamacare but I sharpied out the name and wrote my own over it.)
What a ramble!
Anyway, all I have to do is keep my base riled up. I keep providing targets for the Five Minutes Hate. Any Republican daring to question my actions becomes the next target, and my enormous warchest can go to help my allies and weaken my foes.
They’ll stay in line. As long as I keep my base in a perpetual lather, I expect my party members would remain a bunch of spineless weenies more interested in being reelected and getting that graft than being any serious competition. A few bribes here and there may sort out the rest.
I’m already good at spouting off random, vaguely insulting crap. Now that I sound exactly like Trump, because I AM Trump, my impersonation is nearly foolproof. Trump will make the world an angrier place, because “my” base is blinded by their anger. I’ll make it a better place, and they won’t care about the provenence of it, because we’re pwning the libs.
(Though I guess it would make true social change harder. Well, if I piss everybody off enough, all the liberals will rise together and vote in an even older man than the body I’m in.)
I once fantasized this eventuality, being a unifying and inspirational (or at least relatively normal) presence in the White House, while enacting the less destructive elements of the party’s agenda in a spirit of compromise where possible, to the amazement and horror of both Democrats and rabid Republicans.
This however did not involve looking in any mirrors or interacting with Trump family members. 
*More commonly I have fantasized about being the young Nicholas Romanov in Czarist Russia, avoiding marriage with Alexandra, meeting with young moderates in the Duma and overseeing a gradual and peaceful transition to true constitutional democracy. Sadly, in these fantasies I generally wind up being assassinated either by diehard aristocrats or revolutionaries. 
My first thought is I’m sure he’s got a hookers and blow number on his phone. So I’d spend the first week or two in the White House hip deep in hookers and blow. Melania didn’t move in for 5 months so I might go at least that long. If I’m not impeached during that bender I’d sober up and use the binge as my excuse for a personality change.
Well, only if you wait two years and the election of 2018 plays out the same as it did in our reality. In 2017, Paul Ryan was still Speaker of the House.
One Doper made a good point - there are some ways one could “piss off the libs” (to a conservative audience) while being even more liberal than the libs.
“Abolish Obamacare!!!”…by introducing universal single-payer healthcare which beats the ACA by a mile.
“Watch liberals explode in rage as abortion rates plummet in half!”…by providing contraception on a vast widespread scale.
Increase taxes steeply on the rich…“Watch me tax money away from rich liberals like Bezos, Gates, Zuckerberg and every Hollywood celebrity!”
Taxing the rich is definitely something that a Trump imposter could get away with doing. “Yeah, it’s about time those rich librul elites paid their fair share!”
A poster a couple posts up was commenting on my post, where my central theory was that any Trump agenda could be pushed through simply by framing it as antagonizing liberals. “riling up my base” is one of the ways I phrased it.
The tax thing, though, is the one that would have made me take pause for a bit. Riling up the base may not be enough.
The Koch brothers spent an awful lot of capital undermining corporate taxation and regulation, and anything going against that would butt up against the fiscal juggernaut that helped make the Republicans where they are. The Koch trough is big and deep, generously stocked for the elected piggies to feed from, so kicking that source of grift over is best done with care and as much finesse as the preznit can manage.
(Did I just think “they can suck my Koch!”? No, ahem, never. It’s not pronounced like that anyway. “They’re probably pepsi drinkers!”)
However, the surviving brother did get it into his head to hate Trump, but I couldn’t begin to say if his rage was effective or not. (They/he) did work from the shadows, after all, and Trump didn’t get reelected. It’s just something to coonsider.
I’d plan to keep us out of any shooting wars, Double some of the stock indexes, and create enough padding that I could give everyone a couple thousand bucks to help get them through an unexpected event.
I have a very low impression of the collective intelligence of Trump’s followers. I’ve seen no evidence that they do any thinking of their own. They just believe whatever their leader tells them.
They decided they opposed abortion, LGBT, single-payer healthcare, Black Lives Matter and Antifa because they were told they opposed these things. But if Trump told them they supported these things, they would all nod their heads and agree that they supported these things and always had.
“I could stand in the middle of Fifth Avenue and shoot somebody, and I wouldn’t lose any voters, OK? It’s, like, incredible.” - Donald Trump
Abortion rights? “Ha, if those liberals are dumb enough to kill their own children, I say we stand back and let them do it. In fifty years, the only people who will be left will be conservatives.”
Thanks for the replies thus far.
Now, if we set politics and policies aside for a moment and just focus on the stealth-undercover aspect: how long do you think you could pass yourself off as Trump himself before someone would notice something was seriously amiss - “something about the Donald just ain’t right!”?
Could you pass in the presence of Melania, Eric, Donald Jr., Steve Barron, Mitch McConnell, the media, etc. for one hour? 24 hours? One week?
This is an interesting question.
But how much legislative power does a President have by himself?
I live in the UK with the wonderful Universal Health Care. So if I were Trump, and I wanted to expand Obamacare dramatically - what would the Republican majority in Congress do?
I immediately find the nearest Secret Service agent, demand his sidearm, and put a bullet in my head, because as much as I detest suicide, I couldn’t stand to live as him for any length of time.
Beef up the pandemic response framework, so when COVID19 arrives, I look like an effin genius.
I’m extrapolating time travel and future knowledge from this scenario.
As long as they got their miniature American flags they’d be happy.
Damn Smapti! You shouldn’t really have that hard of a time, you already know how to talk like him.
But I can appreciate how serious you take this by your statement.
That is funny, considering the post just before yours. QED is usually written after the proof of the statement, but OK.
This seems to me to be the obvious answer, although not because of personal discomfort or anything.
Tweet “I have read all the secret info, it’s incredible. Q is fake news, the border is fake news. Republican Weasels don’t care about America. Everything was a lie. Don’t vote, people - big Scam! For losers only. They’ll try to make me pay, but Trump will tell you the Truth!”
Then blow Pence’s brains out, Stephen Miller, whoever else is handy, then myself.
If you think it’s ethical to murder a bunch of people in this hypothetical, does that mean you’d do the same if you had an opportunity in the real world?