I don't know of a "whole" good RV dealer/repair shop and you won't find one that specializes in HRs (I have a 2008 HR Scepter 42PDQ). Just about any good RV place can and do work on all brands. Not all do mechanical work. I live in eastern Ontario so around a day's drive from where you are so my recommendations may not apply.
I use Precision Diesel in Winchester for any mechanical work. Good rates and knowledgeable mechanics and have used them on three different motor homes over the past five or six years.
I have had a hard time finding a good shop for "house" related issues. I know I don't recommend Sicard RV near Hamilton based on PDI work they did or did not do correctly for the PDI (and a really terrible sales experience!).
There is also a place near Chesterville who did good body work but left some other things to be desired so I haven't been back.
Most things house related I try to take care of myself and usually order parts from the US because they are over 50% cheaper than buying them here.
Chris