Buy Remote Thermostat For AC (controlled by Android app) ?

I do that with my park model... but it has a real AC system. I also leave it on at 80 when we are not there.

You are going to need to be able to access the system on the wifi system you connect to. I use a neighbors wifi as it's more stable than the parks wifi. I had to have him log on to his system with my computer to allow me to connect the thermostat to the wifi.