Pretty much SOP on a pusher, remove the bedroom floor or pull the radiator and intercooler and ac condenser and do it that way. Some chassis ca be done from underneath but not FTLNR.
It's a job time wise but involves no special tools or jigs. The cost is in the hourly labor rate mostly. A reman clutch is under a hundred bicks.
You can actually so it in your driveway, no special skill required (othey than a lot of time.
Motor homes, especially diesel pushers are generally a royal PITA to work on, consequently owners get to pay big bucks for mundane tasks.
In our shop, which is a factory authorized Freightliner franchise, we have 2 labor rates. One rate (lower) for Freightliner trucks and another (higher) for Motorhomes with FTL chassis. Interesting, we are always backed up, winter and summer.
I just saw a Berkshire pulling in when I was leaving the shop yesterday....