There’s a spot in Voyageur’s National Park in MN where you can do a ~200m portage that takes two days to paddle back to. You launch your boat on Ash River and paddle up to the entrance of Sullivan. The portage leads into Namakan Lake and there are dozens of small islands with camping spots set out. your trip back round into Sullivan Bay back into Ash River needs to be timed carefully but is a beautiful and challenging paddle.
There is road access to Ash River and nearby parking, a few bars for when you get back off the water. I’ve done my best to represent it on the picture.
I made that journey over seven days about ten years ago and it is one of the defining trips of my life.