The tent looks fine. As in most tents, even new ones, keep a can of water repellant spray handy to reseal the seams. Also, a poly tarp to put under the tent to help protect the bottom and another to have to put over the tent to help shade it, if the site is not shaded. All that aside - the air conditioner.
First, I believe in getting the largest (most BTU's) unit that you can handle, that still will plug into a standard 110 outlet, you can get one larger, but then you would have to make an adapter of some sort to use it, and they are heavier. I am not real fond of the roll around units for a couple of reasons. Even though most have an exhaust duct that will channel out the warm air used to cool the condensor coils, it still uses inside air to perform that funtion so you are losing air already cooled. Some of these units do have 2 air ducts, one pulls the air from outside to cool the condensor coils & the other exhausts the heated air. Over all these units are more expensive and the BTU's are not as good as a regular window unit.
OK, so now onto the window unit, which is what I use on my 10 X 30 tent. First I made a small platform out of treated plywood, with the front portion elevated about 3 1/2 inches with a 2x4 (standing on edge) and the rear elevated about 1 1/2 inches with a 2x4 (laying flat). The unit will lay on top of this, elevated, not only to keep it off the ground and to drain properly, but also you do not want to make your opening into the tent at ground level either. You can make it taller if you wish. Next, I went to the middle back of my tent, and yes, I cut an opening in my new tent just large enough for the A/C to slide through from the interior side of the tent. When cutting, I only cut three sides and left the top of the flap still attached. This next part is kind of hard to decribe. I got a roll of the wide, commercial grade, velcro and went around the edge of the exterior side of the 3 sided opening, centering the velcro to where it is half on the tent and half exposed over the opening. You will do the same thing with the the other side of the velcro to the flap portion. With this velco you can now close the opening back, when the a/c is not there. So onto the next part. Get a roll of the narrower velcro. You will use one side of this to first cover the exposed sticky side of the velcro that is on the opening, facing inward. The opposite part of this velcro will be put on the a/c unit itself, so when you slide the a/c into the opening, the velcro on the ac will attach to the velcro around the opening and will seal off the opening.
If you want to go one step further, to make it more weather proof, while in use or not, cut a piece of vinyl, plastic, or what ever is water proof to where it is about 4 inches larger all around than the opening. Center it and attach it at the top, above the opening (on the outside), with a good double sided tape, then line the other edges with velcro, so when the a/c is not in place, the opening is now double sealed. When the a/c is installed, I have stuck a little velcro on the unit so this flap will make a little tent over the unit. I have never had mine leak due to a storm, but it would never hurt to carry a roll of duct tape just in case.
Also, the way I set my tent up is where I have a king or two twin air matress at either end. Since the a/c is in the middle, I use 2 small box fans in the middle, facing the ends, to help distribute the air. Try to keep the tent fly down as low as possible to help with loss of cool air.
OK, I am long winded, but finished.
