I'd bring a tent as in summer you can have blowing dust, red ants and the chance of a monsoon. Not much different than weather in Phoenix. I've used a tent in the GC and found it a must. You can use a tarp, but expect to get your stuff dusty and possibly wet. I lived in a canyon north of Wickenburg and have spent a lot of time backpacking in AZ. There's some good places to go in the future. This forum is full of info, but not always the friendliest place.