I wouldn't be afraid of a Class B with over 100,000 miles. Just know you will need to do some repairs sooner rather than later. Very few people completely fix-up a vehicle before they sell it. Anything over 10 years old is going to need something.
A good idea IMO would be to set aside a repair budget of at least a couple thousand before you even start looking. For example: Van is a "deal" at $8,000. Ask yourself if you still want it for $10,000 or $11,000, knowing you'll be spending more money to get it up to snuff.
A favorite trick of used car dealers in my area in to put a brand new set of tires on a vehicle that has a suspension problem. Front end and alignment problems don't typically start eating tires (irregular wear) for at least 500 miles. So you're thinking, "Wow, new tires," then 6 months later, one of your new front tires is completely bald on one edge, because the underlying problem was never repaired in the first place.
Not trying to scare you ... just know that there will be issues, and as ernie1 writes, it all depends on your tolerance (and budget) in dealing with them.
QJane
2002 Sportsmobile RB30
inside a Ford E350 2WD