Last winter I went through the same exercise without having the assistance of a knowledgeable bus guy like Joe. Using the Prevost Mtc. Manual and asking the local truck brake supply house a lot of questions, I was able to complete the job solo.
Paul is absolutely right in that having a gopher would have made the job much easier, enlisting a pal or having a willing female assistant adds both safety and convenience to the job. Coveralls, lots of rags or paper towels, industrial rubber gloves, a big jug of hand cleaner and a good work light make the job much easier.
Once the bus is on jacks with the wheels removed, doing a complete remove and replacement job is the way to go. Once you get started, each additional element doesn't take much more time and when you're done the peace of mind factor is huge. I did airbags, all flexible brake hoses, all brake and tag lift chambers, 2 tank drain valves, overhauled the air dryer and installed two new Norgren valves (sorry I didn't do all of them Tom).
I used the Prevost Parts Book and crosschecked part numbers with parts removed. Aside from airbags, (Prevost) and the Norgrens, all parts were purchased from a local truck parts house. Installed parts didn't always match the parts book which caused some confusion and takeback trips to the parts store. (Unsurprisingly) a couple of calls to Jon were part of the process.
All in all it was a great experience which I'd recommend to any wrench head who has a decent set of tools (a short step up from a crescent wrench and channel locks). It was not difficult but was more time consuming as a first timer than I'd first estimated. The bus was on the jackstands for about 10 days and I estimate about 40 hours including parts runs.