Jeff, I made the mistake of starting with a 36' DP (fortunately used) because of post on here about not being able to get into many NP, SP, USFS, BLM...... did not take long to learn that was not true so traded for a 40'. Once we became half timer a 42' four slide is what we wanted and that was 10 years ago. Trading IS expensive.
Most of the places we stay at out West do not have a phone and by arriving late Sunday or Monday it's not a problem as the weekenders have gone home. A 40' DP will have bigger tanks than any gasser which makes for easier/longer boondocking. We usually boondock for five days/week and then travel and resupply on the weekends staying at a CG where we can dump and get water.
As for the DW driving, there is not enough difference in a 37' gasser (biggest I'd go with a gas engine) and a 40+ DP to notice other than the DP will almost always handle better. I do the 1500 miles from GA to CO in two days and the 2100 from MT back home in 3 as I love driving mine that much. Rarely does the DW drive other than for an hour on a interstate if I want to take a break.
