I know EP 47 - Poplar, Lizz, Caribou, Horseshoe - is a busy entry point during peak season. I am curious if in late June things will be busy and campsites will be filling up quickly. I plan on getting to Gaskin first day and then on to Kiskadinna for the second night. The third night we hope to spend on Rib. I am hoping this time of year things won't have gotten too busy yet. We are making a loop exiting at EP 51.

Always a crapshoot but I think late June you'll be ok.

I did a Cross Bay to Lizz trip quite a few years ago (2012), essentially the reverse of your trip. At least you'll be going downhill on "the wall". Enjoy yourself!

Just curious if you have ever seen Kisk? One of the campsites is decent but I thought it was kind of an ugly little lake. Mostly just a pass through body of water. Beauty is in the eye of the beholder and it may be a neat place to stay but there will be a fair amount of people just paddling by between Long Island and Omega/Winchell. I would loop down out of Gaskin into Winchell and take in some of the sites there.....maybe climb the big overlook cliff for a view or hike up the little hidden waterfall (both on the south bank), and the shoot for a campsite on Omega and leave Kisk as a backup site. Your route is short so you should have plenty of time to take in the sites.
Cliff view on Winchell....

Very difficult to say, but I'd lean towards "Yes, it'll be busy."

I was in there in mid-July once and had multiple canoes pass by our site, asking if we were staying and if so, for how long. They said they'd checked every site on Caribou, Gaskin, Horseshoe, Vista, and Henson without anything being open.

But I've also been through there in mid-summer with multiple sites open, so who knows. Probably a crapshoot.

I've been in that area in August and had plenty of open sites, been there in June and couldn't find a site anywhere. You won't know for sure which you'll encounter until you get there. Either way just make sure to be up and traveling early in the day and look to set up camp by early afternoon to allow enough time to paddle further or backtrack to find an open site.

If no people, you could have plenty of bugs on that trip.