Jimmy, I don't know what your experiences have been, opening for national acts.. kind of a double edged sword in my experiences..
On the up side: its extremely exciting.. You're rubbing noses with the big wigs on the big stage and you absolutely HAVE to bring it.. Tons of exposure and you never know who's in the crowd: producers, label reps, celebs etc.. If the show is covered by local news, good chance you'll get written in - maybe even a pic in the paper etc.. Its definitely a great opportunity..
On the down side: The going rate for an unsigned opener - even in a huge venue - is $100.. They'll tell you the real paycheck is in the exposure.. Generally the headlining bands treat you like garbage.. Not all, but most.. I've been treated really well and completely crapped on.. You almost never get a sound check.. when you do, it might be hitting two chords and hitting each drum once - while the doors are opened and the crowd is already coming in.. embarrassing.. They give you limited stage room and you're not allowed to bring any special effects or show stuff.. after you're done you normally get about ten minutes to get your crap and get out of the backstage area.. That is, if they let you USE the backstage area.. Had that go both ways..
Most of how and why the headliner treats the opener like garbage is to ensure they don't get shown up.. I've held my own and, in a couple of cases, thought we blew away the headliners.. whenever we have bands open for us, we always treat them good.. like brothers.. cuz we all are, in a way...
Friendship is like peeing your pants.. Everybody can see it, but only you can feel the warmth..