I felt that were getting low on propane so I did a little research on getting more.  It is common for propane providers, not the homeowner, to own the tank and, if so, it is not legal for another propane provider to fill it.  The larger of the two tanks behind the shed said it was from the Home Gas Corp in Housatonic, the town just north of Great Barrington.

The Home Gas Corp is no longer extant as it was purchased by Amerigas, a national chain.  I called Amerigas in GB and they said that their records showed that none of their equipment remains here, although they claimed that if the tank says Home Gas Corp then it belongs to them.

I ended up calling a mom and pop place in Sandisfield called the Southern Berkshire Fuel & Supply (413-258-4500 - 112 North Main Street, Sandisfield).   They purchase their propane from Amerigas and are authorized to fill tanks belonging to same.  They came out and I purchased 50 gallons at, I think, $3.50/gallon, and they will send a bill to me in NY.  The delivery guy, Rich, looked at all the exterior components and, although he's not a licensed inspector, made some observations.

Left: 1000 gallon tank, Right: 500 gallon tank

 There are two tanks: a 1000 gallon, which has been on and in use, and a 500 gallon, which has been off and not in use.  They appear to be connected to each other and the smaller appears to be connected to the generator.  The smaller is perhaps 70% full (which I didn't know when I called to order propane) and Rich thought it was an older tank and could benefit from an inspection.

Gauges on large tank

These are the gauges on the larger tank.  The larger gauge expresses PSI and the smaller gauge shows the content based on a percentage of the tank's capacity, not the actual number of gallons.  You can only fill a tank to 80% of it's capacity to allow for expansion.

Regulator Outside Kitchen

This is the regulator attached to the outside of the house behind the kitchen.  Regulators step down the line pressure from about 10 PSI to less than 1 PSI, which is what is required for the interior lines.  The hole in the regulator that sort of faces the camera is the vent.  According to rich, this regulator is improperly installed in that the vent should face down to prevent water from getting in there.

Regulator outside house near dish cabinet

 This regulator is outside the house near where the dish cabinet is.  It is an older one than the one in the first image.  The vent is visible here, too, but lacks a little screen to keep unwanted things, like wasps, out.  It is also not facing down, etc.

Regulator outside house near screened in porch

This is the regulator on the outside of the house near the screened-in porch.  It is also an older model and, like the one above, has been painted over, which is not recommended.  It has the screen but it's partly been painted over.  I'll recheck to make sure it's okay.

Valve in screened in porch outside front bedroom

This valve is one of two in the screened in porch just outside the front bedroom.  It serves the wall heater there.  The valve leaks slightly when set to the on position.   Once we understood that it was the source of the gas smell we kept detecting there we turned it off.  Rich suggested that all the old, painted over valves be replaced because the lubricant within breaks down and they begin to leak, as this one has.  I inferred that the old regulators should also be replaced and mounted correctly.

Rich's brother is a licensed inspector and can be hired for a service call if desired.