We've been doing it quite a few years. Your plan is sound, you have the time and most of the equipment needed.
I'm very familiar with the type wood you are cutting as I've hunted in Tx for years.
I would think if you stay after it you can get two cords a day if your doing a 10 hour day. In this area there are so many out of work guys it makes it easy to find good cheap help, we start them at 8.00 an hour. They start out stacking limbs and splitting and if they are a good worker we'll put a saw in their hands and pay them a little more.
If you are serious about this endeavor, I would invest in a bigger saw asap, it will increase your production and make it much easier as well.
As another member mentioned the most important thing to do is document EVERY expense you incur in the wood cutting business. Gas for saws, two stroke mix, chains, files, maul handles, everything, it's the only way to tell if your making any money plus you can write off most of the expenses if you own a farm, we write off all we the accountant will less us.
As St. Louis Wood stated if you can find you commercial accounts to sell to it is much easier to deal with. You possibly may find woodlots in the Dallas/Ft.Worth area that would take all the wood you can provide, some might even pick up once you have accumulated enough.
You need to look at saving all you can on chain and disposable supplies like bar oil/ two stroke mix files etc, look at the site sponsor Baileys, order you a catalog.
The woodland pro chain, woodland synthetic two cycle mix, files etc are usually cheaper than local purchase. Wait till they have free shipping on orders of 200.00 bucks and order what you need for need for the future and save the shipping cost.
With mesquite being your main product I would prolly wait until the Stihl 440 is reintroduced this spring. Stihl is bringing it back due to popular demand for a short time period, it was probably the best around saw they ever made. Keep the little husky for limbing. It would last you a lifetime and handle the biggest oak or mesquite in your country.
Word of mouth advertising has been the best method for us, we always put on a extra row of wood on top to make sure it is a cord plus. Trust me customers recognize they are getting more than a fair cord and will tell everyone they know how good of deal they are getting. Exceeding customers expectations is the key to repeat business and long term loyal customers.