If you can fix yourself drain the coolant into buckets, remove hose, take to NAPA or other store and get new hose.
If not then here is the listing of mobile mechanics on YELP
https://www.yelp.com/search?find_des...harlotte%2C+NC
Start calling, if the one you called doesn't work on RV's ask for recommendations. Eventually you will find someone.
If you have a toad I'd go get some compatible coolant and or enough to do a change.
But the campground may not like the idea of doing extensive work on your rig. If there is a shop close you might be able to drive there, fill up the surge tank, loosen the cap so your rig won't build pressure, see how much it leaks when you start the engine after the thermostat opens. It may not leak that much and you can make it to a shop.