I don't think you mentioned if it's a mountain or road bike... If mountain you might think about a mat or protector for the car, as you can end up with quite a bit of dirt after a slightly muddy ride! I have a piece of canvas cut to fit the back of my Santa Fe. It goes in nice and easy chain side up. I have learned to be careful loading it, so I can load with my khaki's and not get dirty.

BTW I have had helmets start to melt over 100F. Maybe they were already partly defective, but the foam just started melting for lack of a better word. It looked really weird. The bike store guy was impressed when I took it in and asked if I should replace it... (yes) So I take my helmet inside with me now if it's going to be much over 85-90 outside.