If we are looking for Freeway access then the Irvine Spectrum might be a good bet. Its right at the intersection of the 5 and the 405 and is pretty easy to get to.

It also has several restaurant/bars that could support a get together. Fox Sports Grill, Crazy Horse, PF Changs, Champs, etc...

They may not be specifically kilt friendly but they are all pretty used to seeing me by now. I just got asked by the girl in the cigar store there "Do you even OWN any regular pants?" (After seeing me in a Choc Workmans, Black Workmans, and now Nightwatch Camo)