There are a number of smaller locations around the Four Corners. Monument Vally, Valley of the Gods, Gooseneck SP (possible boondocking site), Rainbow Bridge NM, Hovenweep NM, Canyon of the Ancients, Black Canyon of the Gunnison, Colorado NM, CO Hwy 141 a very scenic drive, Great Sand Dunes NM, and a lot of Colorado and Utah state parks: Pink Coral Sand Dunes, Cedar Breaks are just a couple of them. We used Cortez CO and Monticello UT as a home base to explore most of those 4 Corner locations.
If you did the South Rim of Grand Canyon then the North Rim offers a different view and Pipe Spring NM and Vermillion Cliffs are both in that area. Escalante UT has a lot of slot canyons as does Capitol Reef. Those are something you might add to your todo list. Hiking in and out can be strenuous for us flatlanders tho.
We actually have no problem with repeatedly visiting favorite parks. We never feel like we've seen it all. But we do hike and take those dirt backcountry roads to explore. We've been to Bryce 3 or 4 times over the years and a couple of times to Capitol Reef. Yellowstone, Yosemite, Tetons, North Rim, Zion and others we've also done repeated trips to over a 30 year period.
