Do you need reservations?

I was able to secure a campsite easily on a weekday towards the end of the season ( middle of Sept)

For a guaranteed spot, yes. Unfortunately usually with reservations, at spruces campground you have to reserve the campsite at least 3 months ahead of time otherwise it's sold out. Unless you're lucky enough to get an empty campsite that the previous people just left. There are picknick areas as well.

Through May 16th all spots are first come first serve. From May 17-Sept 30 the majority are reservation spots, but there are still a handful of walk-up (first come first serve) spots. Oct. 1 - 31st switches back to all walk-up only.