If you live in an area with seasonal changes and snow, an AWD or 4WD is highly recommended. If you plan to travel only during warm seasons, a 2WD is perfectly capable of handling those types of road conditions.
Don’t get an old van unless you don’t plan to drive that much. Old vans come with tons of issues and there is nothing more frustrating than getting stuck in a foreign place with no replacement parts.
Having a good fan like this MaxxAir RV fan is a must especially in summer time. Vans get pretty stuffy unless you have a fan that can circulate the air inside.