I had a wagon like that a few years ago. Such a cool car. I have been trying to remember what I was going to use for a chassis but for the life of can't recall at the moment. When I remember I will post it. I was going to use a GM product because of something I had and the wheel base was only like a 1/2" off from a perfect fit.I don't know anything about the explorer Sounds like it would be fun a can be tho!