Sorry to hear about your troubles. I definitely second your premonition to stay clear of Century's service department. I too purchased my Cougar from them and I am REALLY glad I can fix most everything myself. Anything I can't fix, I will look elsewhere to have repaired (so far, that has been nothing....
)
Sorry I have no where else to suggest as I have no first hand knowledge but I believe Steve Casey's in Wheatridge sells the Montana line. Not sure if they are any better but perhaps worth checking out.
....or drive to Indiana if you have the opportunity.
To me, none of this stuff is rocket science but for sure, there is a right and wrong way to go about doing it. Anything properly researched, understood and if you take your time, will work out just fine in my experience frame-off restoring vintage campers. Problem with a lot of these places is, no one takes their time and they don't keep staff more than a year at best so you are rolling the dice unless you find someone who has done a lot of these. Only place to find that, is in Indiana as jq pointed out.
Let us know how you make out!