If you’re in an area with a lot of other people and there are only a few of you, you’re doomed. You’ll be overwhelmed, probably at night. Better to be somewhere remote.
This again gets back to how specific the OP is about “modern” technology. If I have a 15 ft. cinderblock wall built around my place, will it disappear? If not, then as long as I have that built with enough supplies to make a few crude black powder firearms then you’ll be able to hold off an aweful lot of raging hords. True a concerted effort would get to you, but it’ll probably be awhile before that level of organization takes place.
By the same token, rockets were used in warfare during the 14th century. So could I stockpile a heap of them? I’m pretty sure that would discourage the casual rioting crowd.
I think you’re underestimating how desperate people will get for food. It won’t be like Africa: particularly in Europe, there will be tens of millions of people in very small areas needing to eat and there will be no food. The OP’s timing is particularly bad for Europe because it will be a month or two before the harvest and the farmers will have no means of harvesting enough of the crops to feed everyone, and the food won’t be ripe in time anyway.
Hmmm…again it depends on how stringent the OP is in this scenario. Did all the canned food disappear? Stockpiled MRE’s? If those items remain, it would give you a little wiggle room, as people will be looting those places first.
OP sayeth; canned goods, stockpiled mres, brick walls, & so forth remainn. FC overlooked them in in planning his michief.
ok, given that…revised plan.
Step 1. Borrow all the money I can possible find. Open up every credit card I can, buy as much crap at the “No payments for the first year” stores that I can and ebay it to get more money.
Step 2. Pay some undergrad students cheap wages to do the research I stated earlier. Working backwards from early 20th century technology, come up with step-by-step detailed plans for making machines to make the machines that I’d need to get back to at least high steam power.
Step 3. My present property is in a fairly small community, but still a bit too populated. However I could pick up 3 or 4 acres fairly cheap that’s not too terribly far away. So do some land grabbing. Make sure property has running water nearby. Have to have some way to power stuff for a while.
Step 4. Have cinderblock wall constructed around property. !5 ft. high, backed with an earthen rampart. Makes it nice and sturdy. What are the odds that someone will know how to build a trebucet in my area? Pretty slim I’m betting.
Step 5. Research locations for stockpiles of raw materials/consumables. Food, coal, lumber, steel…ect. ect. Plan to hit these places in the two to three weeks right before the big day. Doesn’t need to be pretty, just hijak the truck and park it on the lawn. Canned food/MRE type stuff a priority.
Step 6. Procure rockets and fireworks that can be turned into weapons. They fall before the technology line and will be a help in detering unwanted visitors.
Step 7. Guard Dogs will help as well.
Step 8. Seed Stock for growing my own food once I’ve secured the surrounding areas.
Step 9. Fend off the masses. Maybe have some pre-dug holes for mass graves.
Not planning on Dopers with visions of world domination I see 
Forget planning for armageddon, I’m going to spend that year working on preventing it. This Fabulous Creature thing’s gotta have some kind of weakness. I’ll assemble a ragtag team of adventurers and we’ll go on an epic quest to defeat the nefarious technophobe and save the world.
Are they plucky adventurers? I am so there!
Why bother with a trebuchet when you can use a ladder?
According to my Calendar, I spend the year preceding the fall of civilization busily bringing about the fall of civilization.
What he said. But i’d daggone sure make sure I had guns, rifles, explosives and whatever else I could use to mow down the evil army of idiots that would probably come looking for my stuff.
Pretty sure the monkeys would’ve tossed most of that stuff into the wormhole.
Remember, it falls on a Tuesday.
Yep. Forget gold and ingots and whatever. Spices will be the (but of course, not the only) ticket for trading. Salt and pepper alone will come to be dearly coveted.
I just finished reading that book.