If your Cal king is thriving, then I'd treat a FL king in very much the same manner. There are really no major differences. The FL ssp. will most likely get larger (up to 6' but usually less than 5')and heavier and in my opinion a better "pet", but all snakes are individuals.
Ambient temps. in the low to mid 80's F., clean water at all times, appropriate sized food items. (they develop a great feeding response generally) etc.
There are quite a few books on Kingsnakes and Milksnakes out there, so read up as much as you can.
I house mine in rubbermaids not aquarium/terrariums, but would say an adult would be o.k. in a 30-40 gal.
They're not notorious climbers, but would use a branch I suppose. A clean dry hide and a slightly damp one at shedding time would help. They can be messy if given a large water bowl as they just "love" to get the water everywhere it seems

I use aspen that I buy in 35lb+ bales, but if you have only a few snakes, you could obviously do with much less.
I am going through and updating my pics at the site below (in my signature) but there are a few decent shots there.
:Mark