Having a TT can be the best thing going or a real PITA, depending on lots of variables. Don't count on over 10 mpg regardless of your tow vehicle and the trailer you're towing. If in hilly/mountainous areas, count on a little less.
My cousin in Houston "jokes" that going into hilly areas in the Houston area means going over the freeway overpass....pretty true.
Are you looking at maybe a trip or two per month or per season? What distance = the cost of gas.
Can you store the TT at home or do you have to pay for off-site storage. That can get pretty pricey, so check on that before you go very far in this.
What is your tow vehicle and its ratings and, if you don't mind saying, what trailer are you considering? We may be able to offer more help with that info.
Will you be paying cash or financing? Not being snoopy, but if you finance, the interest on your loan is deductible on your taxes as a second home. Some would not consider financing, others consider it just part of the ability to get out and camp. Ours happens to be financed at an excellent rate and our payment is about = to a couple of movie/popcorn/coke evenings. We'd rather have our TT and bring our own popcorn.
We camp mostly in TN, MS, KY state parks or COE and pay about $20 - $25 per night including water/electric and sometimes for the $25 we have full hookups. Don't know how that compares to your part of TX. We recently made a trip to OH and stayed at a moderately priced hotel for 4 nights......we could have camped a good many nights for what that cost us + we like having our own bed and our own stuff ready to use. It's very rare for us to go out to eat since we enjoy that part of camping. So the cost of food camping vs at home is pretty much a wash.
You need to think about how you're going to use this trailer, how often, will you store at home or off-site and most importantly, is your current tow vehicle rated to tow this trailer safely and with some wiggle room?
BTW, welcome to the forum and hope we can help you with this.