We opted for 30amp, 13,500btu A/C, and have no regrets.
(Edit: Thanks to Crabman. We've tripped the breaker one time; A/C on, electric water heater on, and DW plugged in her hair dryer.)
Sherm & Terry w/rescues Steve (std Poodle) & Eydie (min Schnauzer)
2015 Jay Flight 27RLS (Camped: 102 nights 2015, 90 nights 2016)
2006 Ford F350 6.0 PSD, Lariat, 4WD, CC, LB, SRW, auto., Camper pkg.