South Dakota does not have any good health insurance plans for full-timers, that is why TX and FL were mentioned. Mail services usually give you a street address to use when it's required as well as the PMB (personal mail box) # for your mailing address. You would then use this address for everything including your taxes. After signing up with the mail service and changing your address you should then follow whatever steps are necessary for that state to become a resident, obtain the health insurance you need, license your vehicles etc. Most mail services have a program in place to assist you with all of this. You should be able to find multiple companies in each of the two mentioned states.
