Welcome:
Here are a few:
Red River Motorcycle Trails park near Muenster--3,000 acres of woods and creeks.
Barnwell Mountain near Gilmer, open weekends, good trails, gnarly hills.
Shiloh Ridge, about 1,200 acres east of Dallas.
Crooked Creek, south of Dallas.
Rip-Char, about 800 acres south of Dallas.
Kiamichi Mountains, millions of acres (really) of rocky trails in oak woods, 3 hours north of Dallas in Oklahoma and Arkansas.
Lake Stanley Draper, in Oklahoma City.
Marshall Creek, Grapevine, just west of Dallas.
Sam Houston National Forest, north of Houston.
And if you ride competition events like cross-country or enduros, you will get to ride even more areas, open only for the events. It's not as good as SoCal, but there's still a lot of riding in Texas.