I've had SMU season tickets on and off since 2000 (when the stadium opened) and I've lived here since 1986.
First recommendation: walk around the campus; it's beautiful. September games can be hot, hopefully it's a night game. Bring sunglasses if it's a day game. Look for a crowd around 15,000- 20,000. You'll be on east side, looking into the sun. But seating isn't strictly enforced and you can move anywhere. The stadium is nice, clean, and spartan (don't expect Jerry World). Food is average at best. Beer is sold. Tailgating is fun, but I haven't found it to be extremely open and friendly. Wearing UConn gear may get some interest. Most SMU fans know absolutely nothing about Connecticut or UConn, except "basketball championships, cold weather, Pilgrims, and lighthouses"
Tourist spots (most already mentioned):
1) the George Bush Presidential Library, on the SMU campus.
2) the Sixth Floor Museum, re: the Kennedy assassination.
3) AT&T Stadium, about 30 miles to the west in Arlington. You can take a tour. Games are ridiculously expensive. The cheapest seats (very top row) for the Patriots in 2015 were $295. Standing room tickets were $112. Other teams are slightly less expensive.
4) Cowtown ... near downtown Fort Worth. You can take an old steam train from Grapevine to get there in the morning and leave in the late afternoon. It's about an hour each way.
5) Sundance Square, downtown Fort Worth. Good restaurants.
6) Dozens of museums and great restaurants all over the metroplex. Don't eat Italian or seafood while you're here. Go for steak, Texas barbecue, Tex-Mex, or Mexican.
7) The Texas State Fair. If it's open, this would be near the top of my list. If you're old enough (like me) to remember the Danbury State Fair, expect Danbury on steroids. It's very cheesy, but fun. You'll want a shower afterward. It's not in the best section of Dallas. I'd try to stay on the fairgrounds property.
The Dallas Morning News publishes a weekend guide with restaurant ratings and things to do with their Friday edition.
They used to say the South ends in Dallas and the West begins in Fort Worth. It's a fun place to be.