I am new to bike touring. I have a tent, using backpacks as panniers and have everything I need for my ride from Pitt to DC this summer. I am interested in some opinions about sleeping gear. I am going in July, and I am from Arizona so 70 degrees and below require a sleeping bag to be comfortable. Looking at the temp ranges in that area, I know I will need a bag and an inflatable mat, but I want something that is not bulky and will fit on my back rack. Any suggestions?