As far as I know, you will not have to pay real estate tax on your boat even if it is your primary residence. Sales tax, yes.
Not sure about insurance
. Would think an insurance company would be happy an owner will be onboard the boat most of the time they are insuring but you never know. I have read that certain insurers do not want their insured boats to be in a hurricane
zone like Florida
part of the year, but I would think you can find an insurance policy. There are hundreds of live-aboard boats in Florida.
Be certain to check with the marinas
you are interested in that they accept liveaboards. Some do not allow them, some have a limited number of liveaboard
Good luck. Be sure the boat you acquire has good A/C, espeically if you are on the western (hotter) coast.