Get a second opinion... I would think that if it's just a gasket, they can do it from the dog house. The question is, what caused it to over heat and what is the extent of the damage ? Engine should have gone into "limp" mode when it overheated and hopefully prevented major issues.
On our Pace Arrow Vision, we had the pressure cap go bad....it on what looks like an overflow tank, but it's actually a pressure cap. Made of plastic. I caught it before we had any real issue. Just got a new cap. Also, the overflow tank is subject to cracking and leaking out fluid.
Joe
2013 Dutch Star 4338- all electric
Toad is 2015 F-150 with bikes,kayaks and Harley aboard