I've never sleep in a trailer with the second air conditioner installed. First glance is I don't think I would like an air conditioner humming and blowing away just an arms length above my head in our 5th wheel.
You can always park in the shade as much as you can and I like the idea of at at least getting your trailer wired and braced for a second air conditioner.
Having spent alot of time in the Montgomery ALA area in my working years I know how hot it gets there during the summer months...
Roy Ken