Even if you line the roof with solar but only four 6V batteries, you're not going to run even one 15,000 BTU AC for long enough to worry about it.
Why go with smaller panels, because you can get more wattage on the roof. You're not going to get 300W panels around air conditioners or vents or other protrusions in the roof. Even where you have nothing, most of the time if you put two 300W panels side by side, their width together eliminates any room to walk on the roof.
Bill
Nodwell RN110 out moose hunting. 4-53 Detroit, Clark 5 spd, 40" wide tracks, 10:00x20 tires, 16,000# capacity, 22,000# weight. You know the mud is getting deep when it's coming in the doors.