Do you refill propane tanks at rincon tractor supply store?

Yes, And FYI propane is currently $3.09 per pound and a 20lb cylinder holds right at 4.6lb if empty.

I believe so although I've not made use of this service myself

Yes they do. They fill tanks as long. As they are within their exp. Date. It's 2.90 a gallon right now as they fill per what you need and not a set amouny

Apparently, yes...u might have 2 call the store or check on their webpage, just 2 b sure.

Yes