Not sure if it's ok to ask questions regarding the ratings here, but not real sure where else to look.
First, would it be ok to ask controller questions/advise prior to taxi? Or should I direct my questions here (or elsewhere)?
The question I have, is regarding the CAT-07. After receiving clearance through the Class Charlie of KONT, and I only want to maintain 2500' to KEMT, since I am already in contact with ATC, would I be able to continue on through the Class Delta of KPOC without any further clearance request? Keep in mind, I don't really want to have to use the fuel to climb up to 4500. (I'm a low budget pilot, in a little Cherokee 140

Any advise or input is appreciated,
Thank you,
Tommy