It looks like you are getting some good feedback so far but I would like to add some of my own. I have been living in my trailer the past 4.5 years for a work situation and believe that I speak from some experience with what you are thinking about.
1. The trailer condition is most important but the floor plan is very close behind. You need to think about space. If you will be by yourself then a bunkhouse floor plan might not be the best choice. You will be spending a lot of time in this space and it can begin to feel small quickly so think about it and try some different layouts. Keep in mind that you may be watching tv a lot or need a workspace for your laptop etc. Being comfortable is important.
2. The park you are considering looks like it is geared toward long term residents and does have some shade. Being in central TX you should not have major issues with weather but I recommend looking for a 15k AC and an enclosed heated underbelly. You will still need some prep for winter freezing temps but overall you should be OK. I use a combination of electric heat and propane as necessary.
3. In my opinion you could use almost any trailer for your plans. I do not think that you need to worry about a "full timing" trailer since you will not be moving around. Just like anything, items will wear from use. Just keep things clean and repaired and you should be fine.
4. Cost - I could not tell if the park has metered electric or not. And did not find their rates for long term so you need to compare against apt costs to be sure of the best choice.
That's a good start. Feel free to PM me if you want or have specific questions.
Terry