Choctaw Casino in Durant is within hearing distance of the highway, the RV park is out in the open but has all the facilities you would normally expect.
Your route is trying too hard to stay on superhighways. When we were making the run from Tulsa to M.D. Anderson every few months for three years, we did not go through Dallas. Getting off I-45 at Huntsville, TX-19 to Paris, US-271 to the Indian Nation Turnpike would cut an hour or two off the trip, depending on what we might have run into on US-75 north side of Dallas. Halfway point on that trip fell between Paris and Hugo. There are a number of decent, not fancy, RV parks on US-271 between Paris and the Red River. Slogging through southern Oklahoma on US-69/75 can be the pits, even with the recent upgrades to take care of casino traffic from Dallas area into Durant.
There are even more direct routes to NE Arkansas from Houston, notably through eastern Texas to Texarkana, I-30 to Little Rock, then US-65 north.
Along your original route, when we would get caught needing to stop around Lake Eufala, our preference was the Checotah KOA, at the I-40 Pierce exit, between the Indian Nation Turnpike/US-75 and US-69 exits. Our RV club would go there once or twice a year, because of how well we were treated. Can't say now, I think it has new owners, new management, since last visit.
Expect water and power hookups at gravel or concrete RV sites in Oklahoma state parks. There will be dump stations on the way in or out, or in another campground nearby if the park has more than one camping area. Oklahoma mixes RV and tent/camper sites. I've not stayed at Arrowhead, there are parks I like better in that part of Oklahoma, but they are not close to your route.
Tom Test
Itasca Spirit 29B