The parks are too widely separated to find a common jump off cg. Bryce/Zion is one set. Arches/Canyonlands another and Capital Reef and the North Rim are mostly by themselves. We spent a week in Cortez (Mesa Verde, Canyon of the Ancients, Hovenweep and some state parks) and another week in Monticello (Canyonlands Needles District and Arches) this year. Monticello is higher and cooler than Moab and doesn't have the tourist trap feeling.
A couple years ago we spent 8 days in Escalante and did Bryce from there but were mostly interested in the back roads in the area (Dancehall, Devil's Backbone and Hole in the Rock ect) You need a reliable 4WD for that tho.
For Capital Reef we did a week in Torrey (I think at Wonderlands RV park) and stayed a CG which doesn't appear in rvparkreviews at Jacob's Lake for North Rim.