I feel you on the high temps and struggling A/C on a 30amp circuit. Here on Alabama it gets in the high 90's and 80% humidity. A couple things we did that helped us.
1) Put foil backed vent covers in each roof vent.
2) Paint the outside of your skylight white, still allows light in but helps reflect heat.
3) Get some rolls of Reflextec (Not sure of spelling) foil insulation and cut to fit on the inside of all of your windows.
4) We had slide out toppers installed when we purchased our FW and that helps keep the top of the slides cooler
Hope this helps