C.K.
S.,
We have been to Disney NUMEROUS times and I will tell you we have done it both ways but the one that works for us is the nap at the hotel. I have 2 boys, 6 and 3 and we have been going since my first was almost 2. WE go early and stay until lunch/nap time, come back and rest (all of us) and then go back refreshed and happy (all of us). We can also stay later and enjoy more of the park.
What are you going to do while they nap? Sit somewhere? WHy not sit in the hotel and relax as well. The twins will probably sleep better in the hotel without the noise. Disney is an overwhelming place for everyone! Good luck.