Well, since my three kids don't all nap at the same time and when we've tried to go back to the hotel for breaks (not necessarily naps) we've had our only melt downs at WDW, we definitely just let things happen in the parks. I find that leaving is much more problematic (even with our own car or staying on a direct route via monorail/boat/walking); weve given up on thinking that leaving the parks is the best for everyone.
I find a stroller nap, even if it is shorter, and taking an in-park break works best for us. In-park breaks include a monorail/train ride, a sit down meal, a long air conditioned show, a park switch, window shopping, etc. We also never wake the kids up to get to the parks early and we leave when they deem it necessary.
Plus, they never have the same schedule on vacation as they do at home. My oldest gave up napping at home four years ago, but still does nap at WDW. The baby sees getting out of the stroller as time to be energized. My middle one NEEDS his nap and I dont see that ending soon, but will cut it short if hes interrupted (transportation, etc) and thats worse than no nap. Lifes short. Go with the flow on vacation (for us) and things always fall back into place within 24 hours once home. Of course, my kids will sleep on a fence post if tired.