Ten years ago I made the mistake of listening to those on here that insisted 36' was the max for SP, NP, Blm. Bought a used 36 DP and it did not take long to realize this was not true, so bought a 40' single slide. Once we became half timers bought the rig below.
I now say "Buy more MH than you think you need... ONE TIME. Do not let those that say 41' is too big change your mind for FT use. Retired FT equals twice the husband on 1/2 the money in 1/10th the space. While only half timers spending three months each winter in Fla and usualy three months out West boondocking 5-6 days/week without reservations. I do not find my rig to be too big. Yes if you show up Friday afternoon thinking you'll find a site big enough will not work but show up Sunday afternoon or Monday and I'm able to find a site big enough. Often it's the road and trees that are a bigger problem than the sites so sometimes we take the toad first and check things out. There are plenty of self service/no reservations public CG's in or near most NP that have some sites bigger than their listed max.
A 41' tag axle coach will have a better turning radius than a 39' non tag plus you need a tag for enough CCC for FT.