I have an 2007 rav4, living in Colorado where in 20 miles I drop 1,000 feet In elevation every day to go to work. My front rotors are slightly warped, only noticeable during medium braking pressure. Would it be worth the need to replace pads more often to get a bit more cooling factor from Drilled rotors to avoid warping? Or is there a better option?
A warped disc will usually rear it's ugly head in all braking scenarios rather than just under medium or light pressure. It is possible that you have pad deposits on your rotors from getting the pads / discs hot, then stopping the car with your foot on the brake, allowing the pads to 'cook' themselves into the rotor. If you re-bed the pads, you may be able to eliminate the vibration.
As for the rotors, drilled / slotted rotors don't really aid in cooling too much. They provide better initial bite and pedal feel because the machined parts give the pads an edge to grab on to, but most of the cooling is done by the air vanes in the center of the rotor (assuming you have ventilated front rotors, which your car almost certainly does).
The best thing you can do when traveling down hill is put the car in a lower gear so the engine slows you down, meaning you won't have to ride the brakes on the way down the hill.