What I've seen is that all RVs are money pits. Class "B"s are more expensive initially, but for cost per mile, they are as cheap as it gets, all things included.
If you want to know what a money pit is, just try fixing water/mold/wood rot damage to a class C cabover, or dealing with delamination issues.
Right now, "B" prices on new models are through the roof. If you can, bide your time for a few months to see how well/poorly the Travato does (as it is built on a less expensive van frame than a Sprinter), or if one can wait a year, until the Transit gets into showrooms and see what upfitters do with that. The Ford Transit is a workhorse, and two out of the three engines offered are turbocharged (read, minimal HP loss in the mountains), so if it can handle the weight, it would be an ideal chassis for a "B".
Both the Ford Transit and the Fiat Ducato (er, Dodge ProMaster) are workhorse vans, and have been handling real world stuff in Europe and South America for many years now. Both are going through some engine/drive changes before they hit the US market, but if they are as good as their worldwide counterparts, it will make some reliable "B" vans possible.