look after one on a motor home here,
pretty easy to work on to be honest, as you say regular oil changes key to kongevity on these,
problem with motorhomes is they are mainly used seasonly so are parked up and left the rest of year,
first thing would be an oil and filter change as soon as you get it!
cambelt is not the easiest owing to lack of room to get to it but can be done,
fuel filler pipe often leaks but is reasonably easy to change with gadget hands, I had scrapes and scratches all up me arms!!
front brakes can corrode badly(discs) and also wear owing to the weight if the thing, also fluid is never changed!!
rear brakes or at least the drum ones never seem to give trouble athough the h/b cables can sieze if not lubricated, wheel bearings on the front take a hammering but once stripped and regreased every couple of years are ok, propshaft has greae nipples! use them!!
tracking goes out easily owing to peoplke trying to get them into tight position or bumping up kerbs etc, check front tyre wear, also check all tyres for age cracking where they have been stood! common occurence and can lead to atryes with 5 mm r more tread being scrapped!
jm2pw