Freightliner in Springdale services a lot of RV's, but you'll have to pay the Freightliner rates. My last service there was over $800.
We spend a lot of time in Branson, MO and many have Branson Motor coach service theirs. I had mine done there last week, just under $500, but a lot of the cost depends on the filters. I was charged for 1 hr. @$155, the rest was oil and filters. You can look them up, lots of good comments, plus you have an entertainment town to explore while you wait.
2019 Fleetwood Discovery LXE 40M w/2012 CRV toad