I thought that using a scuba cylinder would be a good way to go, since I don't own a compressor for air tools. But, I don't have whatever adapters are needed to make the connection between the LP hose and the faucet.
It looks like a key part is a BC inflator post to 1/4" male NPT adapter, like the top item on this page:
http://www.divegearexpress.com/regulato ... _npt.shtml
Now, it is easy enough to order from DGE, but it is NOT easy to buy that $2 part without throwing in another $100 of stuff to justify the shipping costs.

Or, if there is another way to connect a garden hose faucet to a LP inflator hose, that's good to hear too!