The cheapest part of the motorhome life is buying it. There will always be routine maintenance and it is reasonable for the most part. It is the unscheduled maintenance that can be very expensive. Used fluid analysis can give inside into problems, I'm told the most common problem in diesel RVs is related to cooling system maintenance.
Working and living out of a MH requires room, for elbows and for stuff. A tag axle MH will give you the most carry weight. Amenities that seem frivolous upfront become required after a bit, like endless hot water. Make as few compromises as you can afford, the slightest irritant upfront will be a real problem in a year of occupancy. Peace and quiet while traveling is at a premium, there is no substitute for haveing the engine 40+ feet away.
Jim and Jennie, Cats=Bittles and Potter, 2000 Dynasty 350 ISC
2013 Silverado 4x4 Towed with R1200GS in bed.
PROV23:4 Do not wear yourself out to get rich; have the wisdom to show restraint.