As one of your resident Sooners, I thought I'd chime in. Wichita Mountains area is a good hiking spot with terrain that is similar to Enchanted Rock in places. Lots of granite boulders, canyons, and wildlife. As mentioned above, the Charon's Garden is the most popular hike, along with Elk Mountain. I found this resource that mentions trails I've never heard of but look nice:
https://www.hikingproject.com/directory/8013028/wichita-mountains-wildlife-refuge
If you're camping, Great Plains State Park is nice:
https://www.travelok.com/state-parks/3201
If hotel, I'd suggest Quartz Mountain or a hotel in Altus. Altus is a nice little town with an Air Force base.
Lawton is indeed a shithole. Avoid.
Restaurants - Meers is a must do. Several good restaurants in Altus and Snyder, OK, although it's been many years since I was in the area.
Ouachita Mountains and Winding Stair Mountains is completely different area, more akin to Arkansas or Eastern US mountains and forests. I'd avoid hiking their in Fall due to hunting season but some incredibly winter time/spring time hikes. Take a packable flyrod, as every stream is loaded with smallmouth bass and sunfish.