One thing I will suggest, and that I notice a lot of novices don't even think about bringing, is a sleeping pad. A sleeping bag is good at keeping you warm from above, but not good at keeping you warm from below, and that's what a sleeping pad is for.

You don't need anything fancy to keep you warm, a $10-$15 closed cell foam pad from Walmart, or better a $20 Ridgerest pad, is more than enough to keep you warm in the spring and fall.