This Flying J has RV fuel lanes with dump stations built into them . There is potable water too. I didn't have to pay first.
This also has 5 RV parking spaces in front the attached Denny's restaurant. I parked there for a few hours to get a nap. I noted one other RV parked there that looked it had been there overnight.
There are two Flying J Travel centers here, each on the opposite sides of the road from the other. The one with the RV fuel lanes and dump is the one with the Denny's restaurant and Exxon fuel pumps.