Here’s a ferry from Maine to Nova Scotia.
My uncle crossed the St. Croix River border and back in a large wooden wash tub when he was a youngster. Some older kids put him in it and set him off in the current.
I hear catapult technology has improved since I last investigated it in the 80s.
Get a pilot’s license and fly yourself across. I have piloted an airplane across the South Africa/Mozambique border as well as Mozambique/Malawi.
I’d say you should be the sole judge. Who cares if some pedant says “Nuh, uhhh. You can’t count that ATV trip across the Alps – the tour bus you took last month is a 4-wheeled vehicle so you can’t count another one.”
I say the more methods the merrier, and if you get to cross a border in a car, then an electric car, and later a flying car, go for it… and count 'em all.
If discovered, that would result in two trips across the border – one going across, and at some future date, one going back.
I did that! From Les Gets, France I took a ski lift up a mountain, down the backside, up the next and down into Switzerland. Plus I had the most awesome crepes somewhere in there!
Hmmm. For my suggestion I say you go to Mexico and hire a “coyote” to get you back to America. bonus points if you have to crawl through a tunnel.
How about a howdah?
There’s also a ferry from Port Angeles WA (USA) to Victoria, BC (Canada) and the Victoria Clipper from Seattle to Victoria.
ETA. Since you’re in Niagara Falls, maybe try to float over in a barrel.
In line skates
Segway
recumbent trike
glider
mule
back of a squad car
skis
Is that you again, Randy Quaid?
Nothing says commitment like trebuchet.
Human-powered aircraft.
A friend was once canoeing in Lake of the Woods and a Canadian coast guard boat came up and told them they had crossed the border. Nowadays you would need a passport, but back then (probably 50 years ago) a driver’s licence would suffice. You could also wait till next summer and swim. There is a ferry from Wolfe Island (one of the Thousands Islands downriver from Toronto) to some place in Northern NY. I took it once. There is also a ferry between some place in ME and NS. There is a short bridge from Calais (pronounced Callas), ME to Stephenville (I think), NB which I have also crossed. You can take either a bus or train from Montreal across the border into NY.
Ive done that by Jetski but most likely will cross (uniquely for me) on a unregulated boarder on foot on the PCT.
Trojan Horse!
Naked!