My main concern is getting sucked into ER's gravity well, then I'll be stuck orbiting him. Moreover I'd need like 8600 some leafbux to match the 6100 USD / 5000 GBP pot that was offered.
There's dozens of spots like that. I used to live in a town super close to the US border, there's ATV trails, bike paths and even some small roads that zigzag the border with no signage or guards. That was like 2012ish though, so that might not be the case any more, but my province is super slow to do any sort of maintenance or upkeep, so I'm willing to guess there's spots on the Maine / NB border where ER and PPP could square up.
Someone suggested Glacier National Park but it looks like its closed. Not sure if they'd have security guards or cameras, so I'm not sure how good of an idea that would be.