We have a 33ft. 5th wheel TH with two 13.5k a/c's (one in the front bedroom; one in the much larger main living area). On a recent 115 degree day (5 percent humidity) the smaller bedroom area would chill out around 72-74 degrees and the main living area would never get below 82-83 degrees. We used a high velocity squirrel cage fan to blow the much colder air from the bedroom area into the main living area (via the hallway). Temps in the main living area improved quite a bit, down to 79-80 degrees. Although we would have preferred a couple degrees cooler, considering the blistering heat outside, 79-80 still felt awfully nice.
Needless to say, the compressors on both a/c units never cycled for most of the day. We estimated we were using about $10 worth of electricity each day (compressors did cycle somewhat at night). The full hook-ups only cost us $17.50 a day.