I think with any RV, no matter what type, if they offer 2, get 2, if they offer 3, get 3. Better too much than not enough. Anything over the mid 20 foot range in my opinion needs at least 2. Mine comes in at around 30' of box and we're running one 15k AC. Granted, we have deleted skylights, dark windows, and reflective insulating foil in all but 2 windows, but we can maintain 70 degrees in 100 deg temps. Without the minor mods, it barely could keep up.
John and Rebecca Dickson
Emma-7 / Little John-5 / Iva-1
Full Timing Again, Rev B
2013 Ford F-350 Lariat CC LB PSD
2015 SOB TT - With OC's Awning Poles (#8)
At least in Heaven, RVs will be perfect, and I won't have to keep fixing them.