OP, you really need to study floor plans. I see no reason why you can't find a trailer that you can live full time in. I assume with years of military service, you both are used to adapting to different spaces, some small and some even smaller. You both need to spend time looking at how you would live in the trailer. Where you will store your dishes, your clothes, and your toys. Is the bathroom usable on a regular basis? My Son-in-law would have a hard time using my shower regularly, as he is tall and the shower floor is raised. Me, I am barely over five feet so it is fine for me. Are you foodies that you need space for cooking and lots of kitchen appliances or are you a one pan throw it all together type of cook?
You need to sit down and look at how you live, places you lived that worked well, and places that had things that drove you batty and make a list using these as a guideline. (being military, you should have numerous places to think about).. I see no reason that you can't live in a 28ft trailer, and find one that will work for you. I have a 24ft trailer, that I could live in. I personally plan to move to Small to Medium MH when I go full time, but that's because I want the slightly easier travel and set up.