Installing a roof AC is very easy, even the wiring is simple.. But, if your RV is a 30amp you don't have the power to run an extra AC unit. Two roof AC's are found on 50amp RVs. But, you could pull a second 15 amp circuit. I have done that an I ran a 15amp shore connection. Just be real comfy with your wiring and circuit breaker. For a second AC I chose an 11000 BTU and it was more than enough.
Seriously, the hardest part is getting the thing up there. I have done this job 4 times. If the wiring is there and you have the amps it's as easy as falling off of your RV, which you should avoid.
