"I'd be willing to postpone this for a couple of weeks, I'm going to be coming up from Gunnison either day so it's a drive for me too. Maybe in May?"
I'm okay with postponing. There is a chance that I won't have an operable vehicle next weekend, albeit hopefully a very small chance.
My Explorer has a cracked head and goes into the shop on Monday. I don't imagine it'll take the whole week to fix, though.
My JImny is down on power and goes into a different shop on Tuesday - I suspect an issue with the turbo. That could be a longer fix depending on if we have to order parts from Japan.
Assuming I have the Explorer at least it should be capable enough for most of the Fourmile trails - it's a 2nd gen from back when they were actual 4x4 SUVs.