Phyisiologically speaking, I would suggest low altitude cruise. Sure, you will rent an aircraft, maybe "dry" (paying for fuel/oil) and might be tempted to go for economy liter/gallon per hour. I would say, go for 1,500 ft AGL at best. At 8,500-9,500 ft, you save on fuel ok... but you get tired.
xxx
I have flown light planes 6 to 8 hrs a day (in cruise), call it 4 hrs sectors, landing and refuel, in Piper Super Cub, not exactly a comfortable airplane. A more modern Cessna C-150/152 or Piper Cherokee has better seats, consider to borrow a pillow for your back and "behind". You are looking for
hours, not
speed. Take a flying companion with you for conversation, to hold your maps, and keep you awake. Sleep well and full nights, watch your food, light meals before flying, a good dinner before going to bed.
xxx
Avoid drinking coffee (emergency landings for your bladder) but take snacks and some fruit juices for the flight. When tired (if you are), land and take a day OFF... Schedule yourself day by day, do not try to force yourself to a tight program. If you like to get up early, or late, do your flying when you are at your best. You can chat "plane to plane" on 122.9 and frequencies that are close to that one (read the US/AIM about which ones). If I remember well, anything with 122.8 through 122.97 is usable.
xxx
Generally, April is fine in Florida, as well as most parts of the Southern USA, but watch out for cold fronts and severe weather at times, although storms are of short duration. The Southwest is great too, from San Antonio, Texas through California, along the Mexican border but that area would require higher altitudes because of terrain.
xxx
And dont forget a torch (the Yanks call them "flashlight") if you fly at night.
And enjoy your flying - Probably will take you 3 weeks to do 100 hrs...
Happy contrails