How easy or hard is it to keep comfortable ambient temperature within sleeper for extended period if time(i.e while sleeping)?

by Ysabel
(San diego CA)

I m a girl who needs her sleep and am wondering if i ll be able to get it on the road. My main concern is how difficult is it to maintain a comfortable temperature within a sleeper for extended periods of time.

How insulated are the sleepers from the outside world?

Must i wake up and turn on the A/C or heating every couple of hours to maintain a comfortable temperature? .