I think you did fantastically!! :) You have 6 weeks and some folks try to do this in 2-3 weeks.
A couple things: when you leave Grand Canyon take Hwy 64 east out of the park to Hwy 89 north and then pick up Hwy 160 & 163 for Monument Valley. Gouldings is really the only RV park nearby and you can pick up a Monument Valley tour from the campground. You don't want to drive the loop in your motorhome - it's too rough. Reservations for Gouldings is advised - and it's expensive.
You then want to get back to Page, AZ so backtrack on AZ163 to Kayenta, AZ and 160 and pick up AZ98 into Page. There is a massive road repair on Hwy 89 from Page to the intersection of AZ89A and the road is completely closed. However, once you get to Page you can continue west on 89 to Kanab, UT. That part of 89 is open.
You have two stops for Canyonlands and Moab. That's fine but you could really do both from one central campground in Moab. Or...Dead Horse Point State Park for Canyonlands is a beauty. It has electric but no water hookups. Come prepared.
If it's the Canyonlands Needles district you're thinking of which is far south of Moab then yes, you'd have two stops for that and for Moab. The Canyonlands unit near Moab (recommended for you) can be done from one campground in Moab.
Have a great trip. You seem to know how much driving is involved and you and your group are game for it so it's very doable. Enjoy!
