You will be fine. Your trailer is less than 24', which is the limitation. It's not 24' combined.
Given the choice, I'd definitely opt for the Wheeler Peak CG. Yes, the some of the sites in the two Lehman CG's are right next to Lehman Creek in a Pinon/Juniper/sagebrush setting and quite pleasant. But I love the feel of the upper CG with its spruce/pine/aspen forest. When we were there last, the road through Upper Lehman needed some work with lots of pot holes. Wheeler Peak CG definitely has some sites that will fit your rig.
