Favorite university to visit for away games ? I'll steal 6th's list and edit since we've been on numerous trips:
Road games:
Cal (football)
Cal Poly (football)
Irvine (basketball)
Long Beach State (basketball)
Pacific (basketball)
Stanford (football/basketball)
San Jose State (football)
Portland State (football)
Weber State (football)
Nevada (football)
Montana (football)
Boise State (football)
Northern Arizona (football)
University of San Diego (football)
Fresno State (football)
Saint Mary's (football '01)
J Street Tech (football/basketball)
Best: Montana. If you can make it to Missoula, GO. Like 6th said, great crowd, atmosphere, and small town charm tied in with a community who is ALL-IN and rabid supporters for the Griz. It's the biggest big-time of western FCS schools. San Diego (because San Diego) and Boise (similar reasons as Montana but to a lesser or different degree) follow.
Worst: Fresno. Don't go, just don't.