Just so you know, I live in Albuquerque and have never camped at the Fiesta. I'm not sure if GSC uses a campground or has spaces on the Balloon Fiesta grounds but that is where you want to be located. It's getting a little late to plan for this years fiesta but if you can book a spot yourself it would probably save you a lot of money. You really want to be on the grounds for the best experience. You'll have balloons flying right over you. As far as the weather that time of year, you will probably not need any A/C at night but may need it during the day. In fact, you will definitely need a jacket to watch the evening balloon glows, etc. I lived in SC (worked in Charlotte but lived across the border) for many years and it will be a welcome change to get away from the heat and humidity. When I first moved my family from SC to NM I took my teenage sons tent camping in the mountains. It was the middle of July. I told them to bring their winter coats as it would get cold at night. They chose to ignore my advice (they were teenagers so they knew everything) and they almost froze. So if you plan to visit the mountains while you are in NM you may even want to bring a heavy coat. I hope you can get a spot as it is definitely worth the trip. Travel safe.