There's a guide to two of the parks not too far from the Key West Aquarium at http://www.rv123.com/blog/rv-resorts-near-key-west-aquarium/
I've heard recommend Boyd’s Key west Campground, located at 6401 Maloney Ave and Leo’s Campground, 5236 Suncrest Road
Boyd's amenities:
Oceanfront sites
Full hook-up sites with Cable TV
50 amp & 30 amp electric
Dump station and pumpout service
Modem data port (no charge)
LP gas (with charge)
Boat Ramp & Docks
Heated swimming pool
Gift & Convenience store
Game room
4 clean bath houses
Coin laundry
Free Wireless Internet for guests
Poolside Tiki Hut with big screen TV
Picnic Pavilion with grill
24-hour security
ATM
City bus service
Dishwashing stations
Picnic tables
Leo's amenities
Gravel pad, back-in sites
Picnic table, water
Sewer hook-up
Electric hookup (most sites up to 50 amp)
Direct digital cable TV.( If your TV isn’t digital cable ready, cable boxes are available with a $50 refundable deposit.)
Wi-Fi within a 50 ft perimEter of office
Showers
Laundry facilities
P.S> - If you're feeling touristy while you're down there, be sure to stop at "Robby's Marina" in Islamorada to feed the Tarpon by hand.