And I should clarify my California comment.... They don't actually require a "CDL", but they do require a non-CDL Class-A license for heavier/longer RVs. Only for residents but the requirements are the same including requiring a medical exam card. Your out-of-state Class C license will be valid for your RV in California as well.
That said - California only classifies pickups up to 11,500 pounds, so if your future may ever include a potential move to that state, that may be good reason to reconsider and F450 (Ford offer low-GVWR options for the F350, which are a sticker change only, for that reason).