You guys are increadibly lucky to be seeing them, especially with the Fat Cats. They played here in Vancouver at a local legendary blues bar, "The Yale". Lots of folks did come out of the wood work for this, but I was extremely surprised at how little of the regular jamband show goers were actually there. It was a bit more of an old school trucker, biker, blues crowd.
NRPS was amazing and played lots of old favourites.
I highly recomend warming up for this show by listening to NRPS from the 70's as opposed to newer stuff. If you listen to a whole lot of newer stuff, you'll find it really sounds the same as the show you'll see. Listen to lots of the old stuff, get refamiliarized with the tunes, then see it live, love it, then go home and listen to the new stuff. Trust me.
have fun!