This is pretty minor, but hey, I love it.
I threw some Harbor Freight interlocking foam mats in the van and cut to fit the floor. Mainly cuz I was too lazy to get some new carpet, and I figure it was hanging around the garage anyway. It's the stuff that you use on concrete if you have to stand a lot. It's not as beefy (or heavy) as some, but it's way cheap (and there's usually a coupon).
Anyway, it sure feels nice on the footsies, and it kept the floor warm. I didn't realize how much heat I lost through radiation out the bottom. And if you're like me, you end up doing a lot of kneeling down, especially reaching in to get stuff in lower compartments or with the penthouse down. This makes it much easier on the knees.
2001 Ford E250 Sportsmobile with Salem-Kroger 4x4 conversion