Even then, A/C shouldn't suck up that much juice. I rarely notice a difference running the A/C on any of my vehicles. Around town I don't always run it, but when it's above 85F outside I will on the highway as the wind noise can get downright annoying.
As for new tires, get the smoothest tread tire you can. As you live down south winter traction won't be necessary which makes shopping a lot easier. I would suggest going with a touring tire. They're generally biased more toward dry performance and have greater road contact. A more aggressive tread of course, will increase rolling resistance and potentially lower fuel economy. Once you get a few tires narrowed down, check online at the manufacturers website for the weight. Passenger tires will weigh a good 20% less than light truck tires, and offer a better ride. LT tires can be had in several smaller sizes that can fit the Escape wheels.
Sticking with a major brand such as Goodyear, Michelin, Pirelli and Kumho are a few of the better brands. There are a LOT out there. Best thing to do is to check out a tire review site and punch in your size and you'll get a list of tires available that will fit your vehicle.
Tire Rack - Your performance experts for tires and wheels is a good site to check reviews. As you're in the USA, our tire sponsor here on the site can also steer you into a rather good deal. Check him out.
