If you go the 'long way' to KC (instead of via wichita which is the fastest but back to where you started), you can go through Tulsa and see several museums (Gilcrease, Philbrook, Woody Guthrie Center) but if you go off the beaten path but more than a day to get there (it's about 5.5 hours direct with no sight seeing), you can go through Bartlesville, Price Tower (Frank Lloyd Wright building), tallgrass prairie wildlife area and Pawhuska, Woolaroc, a cool museum and wildlife area, Pioneer Woman stuff.
Do you know where you're staying in OKC and need recommendations for that?
I would love recommendations on where to stay! We'll have a car so we'd like free parking if possible.
Between Wichita and OKC there's not a lot (at least right along I35), but if you like antique shopping and Victorian architecture, I'd detour in Guthrie. They have 2-3 streets in their historical downtown that have beautiful old buildings. They are also known for their antique shops. You could easily spend a few hours walking up the Victorian streets and checking out the shops. If you're willing to take another minor detour, just before you get to OKC, when you're entering Edmond, on the old Route 66 you can visit the beautiful red, round barn (by Arcadia, OK) as well as Pops. Pops has a giant light up pop bottle out front and serves thousands of varieties of pop as well as food. You can stock up on beverages for your road trip!
OKC has a lot of cool places too. Since you like history I'd recommend the 45th Infantry Museum. They have tanks and planes outside and then a museum to tour. It looks small on the outside but it's actually much bigger inside. It covers everything from Revolutionary War to present. Downtown has the Oklahoma Art Museum that is very nice. Downtown also has lots of restaurants and is a popular tourist attraction, especially in the evening hours. Be prepared to pay anywhere from $5-20 for parking.The Paseo Arts District has local artists and depending when you're here they have a First Friday Art Walk, where the shops stay open late and food trucks.
As for hiking, in the metro there aren't really any true hiking locations, mostly just leisurely stroll through the woods. Martin Nature Park is popular walking location. I especially love going early in the morning when they just open. We've often seen herds of deer in the morning. Lake Hefner also offers paved trails and beautiful scenery of the lake. There is an active boat club and depending on the evening they may have sail boat races.
If you're willing to drive for about 1 hour 45 minutes you can go south towards Lawton to the Wichita Wildlife Refuge. It is one of my favorite places to hike in Oklahoma! Stop in at the visitor's center. They have staff that can recommend trails based on your time and skill level. The refuge has Elk, Bison, Long Horn Cattle, Bob Cats, lizards, prairie dogs, birds, etc. You can usually see a few bison and cattle just strolling around. We've seen a Bob cat in the morning while camping. The Elk are more elusive though. When I worked at a hotel downtown I'd always recommend the refuge and everyone loved it.
I haven't traveled to KC so I can't offer any suggestions for that drive, but I wish you luck. I've lived in OK my entire life and it really is a great state.
P.S. If you stay in a hotel downtown you will more than likely have to pay for parking. Just a heads up! Outside of downtown you shouldn't have to worry about paying to park.
Roaring is correct re downtown and parking. There are several hotels on NW Expressway that can quickly get you to other areas (National Cowboy & Western Heritage Museum, OKC Museum of Art, OK River activities, etc.) and will offer free parking.
I think Wichita Mountains may be a bit far south but it's worth checking into. A wonderful area.
Thanks for all the great advice! I appreciate it!