Room temperature is perfect. And unlike cigars, pipe tobacco doesn't have special humidity requirements. If you're going to finish a tin within a few weeks, I think you can store it in its tin with no problems. Longer than a month or so and you should probably transfer it to either a mason jar or ball snap lid jar.
Excellent question about light! I've never considered it to be a factor, but I think a chemist would be able to definitely answer.