I am guessing that your 2 air conditioners running at the same time pull about 3000 watts. A 3500 watt generator might get you by if you limit other electrical loads, but the large startup draw for each air conditioner would likely give you problems like blown breakers on the generator, and loss of power. The 5000 watt generator would work better. The tradeoffs are, the larger you go in generator wattage, the more it weighs, the louder it is (but less than proportional), and the more fuel it uses. Also, these are a prime target for thieves, and need to be locked down with a motorcycle-type security chain/lock, or bolted down with security head bolts. The new generation of inverter-type generators are the most quiet and fuel efficient. I had a 3500 watt generator of this type (stolen), and I did a test run of running the 1 air conditioner in hot weather and seeing how long the generator would run. It used it's 4 gallon tank of gasoline in 4 hours. This multiplies out to 8 gallons in 8 hours - hot days often require 12 hours a day of air conditioning. This gives a $28 dollar cost for 8 hours of air conditioning at a $3.50/gallon. That is for 1 air conditioner. And how do you haul around 8-16 gallons a day for your generator fuel??? Also roll in the fact that hauling and transferring gasoline is a significant fire hazard.
I came to the conclusion that if I wanted to run air conditioning, it makes more economic sense for me to get myself to an RV park with 30-50 amp electric hookups, where the electricity costs are rolled into the daily space rental.