We had a 2008 HR Scepter 42 PDQ.
It had 9000 miles on it when we purchased it. About 20,000 when we traded it.
Rode solid, was stable. We had no issues with the chassis, the 8.9L or the 3000MH. By the way the wrist pin issue was on early ISL engines.
The Roadmaster chassis is dated by some standards when you compare it to the plush ride of a IFS chassis by Spartan or Freightliner. Not trying to ruffle feathers - The Roadmaster is reliable, but not modern.
The doors are not that quiet on the series that you are looking at even with good seals and when properly adjusted.
In our ownership we replaced the following on the coach and will comment on these items;
-water pump (house)
-slide toppers, fabric and the thread rots.
-carefully check the moving plumbing and electrical run that moves with the kitchen slide (PDQ floor plan)
-10 shocks - the Monroe's on the Roadmaster are garbage.
-AquaHot Control Board
-Windshield - Prone to leaking and bad seals
-Power Cord Reel Motor
-Shower Door Rollers
-Strings on the Day/Night Shades
-Venturi on the gas stove
-Countertop came away from the wall on the kitchen slide
-1 AC unit
-Replaced LCD monitor for the camera system
-Have a good look at the roof seals, that 42' chassis is prone to a lot of flexing - make sure there is no sign of water damage - check the seal/roof just behind the awning rail ahead of the bedroom slide on the curbside.
There were a few other things, please don't get the wrong idea. Stuff can go wrong on any unit. If I was shopping for a "original" Monaco/HR product again I would take the above list with me.
PM me if you have any other questions.
Adam Hunter and Family.
2009 Newmar DutchAire 4330 (The only DA 4330)
2015 F150 SuperCrew Toad