I would opt to get a species that would do much better in cooler climates, albigs niles savs are all use to having cooler nights and sometimes days in the wild, South African locales of niles and albigs would be the best way to go specially the Cape banded albig, they would tolerate the cooler temps in Northern Florida alot better. I would also think Argus Monitors would be ok in that type of setup. I think that a heat box would be a great idea, with a kane heat mat and also some bulbs hanging from the ceiling. Theyre still gonna wanna burrow so you might even want to stick the kane mat about 2 feet under ground that way the burrow is heated a bit. During the day temps pick up so im sure they will use the sun to warm up. Im thinking of doing an outdoor enclosure for my Indicus and Jobiensis, I will be looking to keep them year round outdoors and will be looking at the possibility of using a warm box to help them when we have cooler days here which are about a week or 2's worth of cooler weather year round here. They only really need it to be in the 70's to come out and bask, they will just take longer to achieve the body temp needed to be active.