Always have a dry set of clothes and have a way to keep yourself dry, especially your feet. Even in 65 degree weather, getting wet can lead to hypothermia, trench foot, and other problems as well as a horrible time on the bike. Probably a lightweight tarp to cover your bike at night as your bike will be soaked if you don't, just like leaving it out in the rain every night. The one idea of yours is great, and it's one everyone should be doing, an overnight tours to test their equipment out.