Can someone tell me what walk-in means for reserving campsites and do they have a swimming area for the kids and can you take your dogs down by the lake as long as they're on a leash

Walk-in refers to sites available as "first-come-first-serve" rather than reservation only. Big lake is not a good lake for swimming: however, the Black River is a short drive away and we love taking the kids and dog out there to. Play in the water!

I believe walk-ins simply means you are likely to find an open campsite without a reservation. Peak season you won't. I wouldn't really recommend Big Lake for swimming. Last time we were there the water was rife with algae. And I am not aware of any reason you can't take your dog anywhere in the area on a leash.