K.P.
We just transitioned too and my son will be 3 in a few months- don't feel like a late bloomer! Our pediatrician suggested keeping him in a crib until he figured out how to get out!
As for naptime, many children give up their naps entirely around age 3, so it could just be the timing. Having said that- 2 hours is a long time for a preschooler to be napping in the afternoon unless she really is exhausted. What we've done with our son is replicated what they do at his daycare.
They have a designated "quiet time" for an hour each afternoon. They try to get them all to sleep and the infants/toddlers usually go down without a fuss. However the 2.5+ kiddos are a crapshoot. During that time, the lights are low and EVERYONE is quiet- if the children aren't sleeping, they are quietly reading books or doing puzzles for that time. On the days that my little guy doesn't want to nap, he lays down and they just rub his back for a while.
You can't force her to nap if she's not tired, so unless she is crabby without a nap and needing to lay down every day around the same time each day, just insist on quiet time for an hour. I would leave out "quiet toys" and books for her and make sure that you are quiet too for the first week or so until she gets into the routine.