Im finishing up my Junior II semester at the Dallas campus and I love it there. We have a few people that transferred from Houston to Dallas after the Junior I semester and from what Ive heard, they are glad they did. I also know a lot of people who love the Houston program and would never want to leave.
Either way, TWU is a great program. The info on orientation and the NET exam should have come with your acceptance letter. If not, I would suggest calling the Dallas campus to see when the orientation is because you cannot miss it. As for the NET, though, I think you just have to have it done by the time the semester starts in January (but dont take my word for it). You also need to make sure your immunizations are up to date because you cannot work in the hospital without them (clinicals will start sometime around the end of February for Junior I's).
Let me know if you have any other questions and congratulations on your acceptance!!