Propane

Is there anywhere on the island where you can actually get a propane bottle refilled and not just exchanged

I can get mine refilled in Ponce but I have to wait or come back later. I always keep two filled

I was also wondering about that -- not only the small 25 lb tanks for the BBQ, but what about the availability of propane delivery for a large tank (100 lbs or more) at your house?

Depending what part of the island you are. I'm not sure in the metro area, in Guayanilla, there is a place that will refill any size bottle. Most towns will have one or two business dedicated to deliver propane. Prices are regulated by the government.