Are there going to be spots that a 35' rig might be a challenge to get into? Absolutely. But there are an awful lot of places you can get into and I've never been anyplace you couldn't get into with that size trailer. I'm sure there are places you can't but I'm thinking they will be few and far between.
Might repost over in the Full-timers forum as there are plenty there that have a 35' rig. Even in the Toyhauler section as they are more likely to be ones that camp at "natural sites" since they often are taking their ATV's, Rail buggies, etc out in the middle of no where to ride.
Good Luck in whatever you decide.
2015 GMC 2500 Denali Crewcab 4x4
2019 Forest River Wolfpack 23pack15
Hope your travels are safe and the friendships made camping are lasting.