Chabot is very pleasant indeed. I was shooting my Bess there Friday. Curtis, who's the RO Friday and sometimes other days, has shot black powder on and off and is very comfortable with muzzleloaders on the public lines. Some of the ROs less so but they're usually pretty open to being taught the rules. :grin:
Unless you're arranging something through the guys you met Sunday you'll find that the closest BP available is in Jamestown which is a couple of hours away (on the way to Yosemite). There's also a few places in Southern CA that sell it if you're ever down that way.