I will add to what has been suggested here...
Central Tx for most around it will be 4 hours or less driving, so definitely make this a Saturday event so those of us with long drives can rest that night before hell on the road back home.
Winnie, I wouldn't suggest.. there is not much out there anymore post-Ike on the beach, but last time I took the ferry to bolivar, i got skipped to the front of the line.
Spring Creek is ok, but too small, and the trails can be brutal on those not used to offroading big trucks. not to mention those with new canvas or vinyl will be hard-pressed to possibly ruin it on the trails as they BARELY fit an M35