I want to put in an A/C that can run when my van is at camp. I usually camp with electricity one day will get generator. Is there a metal cage/rack I can buy to put into my back window or should I build a wooden one? I don't mind taking it in and out but prefer to keep it in when traveling. I have a tire on the back of my '95 GMC 2500 Vandura Explorer Conversion Van. Have to do a few mechanical stuff but I love it and it is just under 100,000 and physically it's in great shape. If I put it in the roof I have to give up the sun roof which actually is not so bad considering I live in Texas. It would be cheaper to put in one in the back window but I don't want it to look ugly.