No simple answer to your question and the following are generalizations based on my prior work experience in legal residency/domicile and are does not constitute legal advice.
Your domicile is determined by your presence in a state on a permanent basis, until you abandon that state to become a resident in another state. You cannot be a citizen at large, even though some full-timers would like it that way.
You're a WI resident by admission. If you buy the MH in FL, and leave it in FL for a period of time AND not take it to WI, you will probably have to title and register it, AND pay taxes in FL, until you take it to TX, and MAY have to pay taxes again, although you MIGHT get some reciprocity. Remember for example, each state differs on how many days one has to establish domicile and title and register vehicles. Of course, you'll have to pay to title and re-register it in TX. It may or may not be cheaper to just pay WI what it wants until you move to TX.
It might be better to purchase the MH in FL and have the dealer (if any) ensure your documents show it will be registered in TX, and do whatever you have to do to perfect that registration at time of purchase, i.e., drive it to TX on a temporary tag, but that gets into the following:
If your intent is to become a TX resident, you need to abandon WI (but can still own real estate there), establish an address in TX, title and register all your vehicles there, obtain a TX drivers license, register to vote, open a bank account, get a library card, buy property there,pay taxes there, etc. No, you don't need all of that at the same time, but definitely the address, drivers license, and the vehicle registrations go a long way in proving domicile. Most of all, your physical presence is generally required. (And yes, I know, there are some states that make it very easy to establish domicile without presence, but not FL and TX.)
Bottom line is you need to make everything clear and not set yourself up for WI, and to a lesser extent, FL, to come after you for taxes. Some greedy states, MA, MI, VA and NY come to mind, that are tracking down tax avoiders for every last dime, so be careful. Even if another member comes online who's done the WI to FL to TX thing, trust but verify their advice.
