Hi Momto2!
I travel with and use an electric cooler (mine is from Coleman) that can both plug into a cigarette lighter (12V DC) while traveling and with the included 120V AC adapter can plug into the power post (or use an extention cord) at a campground with AC.
Here is a link:
https://www.coleman.com/powerchill-40-quart-thermoelectric-cooler/3000001497.html
No ice to buy. It lowers the the cooler temp about 30-40F degrees lower than the exterior air temp and actually works quite well. But that brings up two points: in very hot weather (like 90F+ that we have here in Alabama), my "adult beverages" only get chilled down in the 50s. Still safe enough IMO for fresh food, meat, and vegs but I like my beverages in the low 40s, if you know what I mean.
On the other hand, when night temps get cool (50F or lower), I have awakened to find slushy ice in my "adult beverage" cans because the low night temp coupled with the chill differential caused them to start the freezing process. So on cold nights I unplug the cooler before going to sleep (it will be plenty cold enough from the air temps over night) and then plug it in the next morning.
For a November trip to the Fort, you probably can leave it plugged in around the clock and be okay but you can manage it the way I said. I like buying most/all of my food at home and bringing it with me so I don't have venture to the local publix when I arrive in Orlando. Later in the trip I usually end up there (or walmart) though.
I also like throwing some diet Cokes and bottled waters in the cooler while travelling so I don't have to pay $2 a piece for a 20oz at the gas stations en route.
So that's what we use. We've had it for over a decade and it still works great.
Bama Ed
PS - I have also found that keeping the cooler in a shaded location helps keep things cool inside. Extended direct sunlight is not helpful to the chilling process.
PPS - I do have a small fridge in my trailer but this is my travel cooler while in motion and overflow cooler while at the site.