I was stationed at Fort Hood as well and got out of the Army in December 2009. My home lodge is actually in Copperas Cove. As I am sure that you have already gotten your answer from S. Courtemanche, I can offer a little bit of information on being down range and Masonry. He also might have touched base on a bit of this.
I know that you might be excited to join the fraternity, but my advice would be to wait till you get back to Hood. Talk to some brothers and try to meet some that are in the lodge there in Killeen. You can do this via that internet through this forum, or by contacting the Lodge Secretary, which you can find that contact information from the Grand Lodge's website (if it is updated). I also have a friend of mine that is a member of the lodge in Killeen, so if you still need someone to make introductions, let me know. They will be more than happy to talk with you and correspond with you till you get back home and welcome you to the lodge once you are back.
The reason I say it is better to wait, is a lot of the time there are guys conducting lodge when they shouldn't be (without a charter). And sometimes if they do have some sort of charter, it can be from a lodge or grand lodge that is not recognized by the Grand Lodge of Texas or even any other jurisdiction you may want to be part of in the future.
When I was in Iraq, I was at a few different bases where guys would see my ring and tell me they had a "lodge" on the FOB and wanted me to come join them. I even had a few buddies of mine that had shown a big interest back in the states to become Masons but didn't have time before deployment. While down range, they attended these lodges and became "master masons", but I couldn't be there with them as I was still a "young" Mason at the time and didn't want to be where I wasn't supposed to be. From my understanding at the time, the Grand Lodge of Texas prohibited Masons from attending lodges that were not recognized by the GLoT and I still didn't have a clear picture on what to look for to know that they were recognized. I am not saying no lodges there are recognized, cause I don't know for a fact which ones are or aren't, but it's best just to make sure you are going about things the right way.
I do think that it would be awesome to go through the third degree down range...lol If you have any questions at all, want to correspond about this stuff, or even want me to get you in contact with a brother out of the Killeen lodge, by all means PM me. Stay safe and I hope this helps out a little bit.