Adam and Karl,

Thanks for the advice.  I found a place called Euro-American RV where a very
helpful and knowledgeable guy also told me that the valve is no longer made.
He did, however, have a $13 rebuild kit made up of some o-rings, a screen and
some special lubricant that he said might fix my leaking auto stop valve
(model 430).

I bought the kit, installed it in just a few minutes using the included
instructions, and was able to get the tank filled (2.7gal) and we ran the
fridge for the past four days on our camping trip. :)

Roger