Rent a car. Since you are staying pretty far from mass transit, it will be indispensible. You can get a ridiculously low price through Hotwire. Driving in Dallas/Fort Worth is no worse than any other large city.
Don’t forget Fort Worth, it’s a little different than Dallas and has a lot to offer as well. The Gaylord is more or less equidistant to both cities.
Things to buy:
Half Price Books, several locations, the one at 5803 NW Highway (Dallas) is the biggest and best. A small regional used book/music chain with great selection and prices, it’s a far cry from the dusty, understocked stores that one
typically sees.
REI, on LBJ Freeway (Dallas/Farmer’s Branch). Not sure if you have any out your way, if not, it may be worth a stop. While not as huge and opulent as some of their locations, the Dallas REI has pretty much anything you’d want for camping/hiking.
The Trinity Antique District (Dallas). Lots of antique stores, if she’s into that. On Industrial Blvd, there a 2 big adjacent ones called Lost and Found. There’s another surprisingly big place that occupies 2 old houses and their outbuildings on (I think) Lemmon, but I don’t know the name.
There should be an outlet mall around the metroplex, but darned if I know where it is.
The Highland Park Mall is smallish, but is full of expensive designer fashion type stores. Bonus-it’s one of the oldest shopping plazas in the US.
Things to see:
The aforementioned Dallas Museum of Art and Arboretum.
Just driving around Highland Park and University Park, looking at the enormous houses is kind of fun, in a ‘see how the other .00001% live’ kind of way.
The Kimbell Museum in Fort Worth has some very nice European and Meso-American stuff and usually has a traveling exhibition going on.
The Museum of Modern Art is across the street from the Kimbell and is also reported to be good. There is no admission fee at either museum.
The Fort Worth Botanic Gardens are beautiful, particularly the Japanese garden.
The Stockyards in Fort Worth are touristy, but fun if you want to see longhorns and cowboys and maybe buy some boots.
The Monning Meteorite Gallery at TCU I Fort Worth is just awesome, if you like meteorites (doesn’t everybody?), otherwise it will probably bore you. As it is inside the Geology building, check the hours ahead of time.
Things to eat:
Arcodoro, on Routh St. (Dallas), fairly expensive, excellent Sardinian/Italian food in an interesting setting.
La Duni, on McKinney Ave. (Dallas), fairly expensive, Latin fusion food, primarily Brasilian and Argentinian influenced, really nice dbaked goods.
Fadi’s, at least 2 locations in Dallas. Cheap to mid-priced. Huge selection of fresh, well done Mediterranean food, and a lot of it. A good bet for vegetarians. Apparently related the Fadi’s places in Houston.
Grimaldi’s, McKinney St. (Dallas). Mid-priced. It’s an outpost of the famous New York coal fired brick oven pizza chain. I’ve not been yet, but many people like it, although it might not be quite as good as the transcendant experience at the original.
Byblos, near the Stockyards in Fort Worth. Mid-priced, very good Lebanese food. Bonus-attached hookah bar, also belly dancing on some nights.
Central Market, Lover’s Lane (Dallas) and somewhere in Fort Worth. Immense supermarket, selling mid- to high-end foods. It’s like Whole Foods with better prices and selection, and without the snobbery. The produce section alone is worth a stop.