We spent three weeks in the Southwest in 2006. My spouse is also a teacher, so we had a similar schedule.
Kodachrome Basin was disappointing when we were there in late June -- hot, dry, and not all that photogenic. Bryce Canon, just a few miles up the road, was much better. (The elevation gain made most of the difference, I think.) Spectacular views at sunrise and sunset, and great hiking in the canyon.
I would highly recommend the North Rim of GCNP. Higher elevation, fewer people and cars, more remote feel.
We liked Moab; Arches National Park is very cool for sunrise photography, and the town is worth a visit. Mesa Verde was cool, but very touristy in the summer. Not sure what you can shoot there.
I know we missed far more than we saw -- I could spend the rest of my life mucking about that area, and it would be time well spent. Have fun.