My wife and I usually fly in and stay at the Hilton (Post Oak) down the street from the Galleria. There are some nice restaurants in that area. And because my wife travels so much, the room (even upgraded to a suite) is usually free.
It's a short drive from there to Reliant. We usually park in the platinum lot.
I've never really partaken of the tailgating. We just go in and find our seats and watch the teams warming up.
If we don't stay at the Hilton, we stay with my mom. I don't think you want to do that. Her rates are low but it's a longer drive. And there's the whole little yippy dog thing to deal with.