I did that sail, but from the other direction. Trailered up to the Apostles, then sailed over to Knife River in a ComPac 23. I say "sail", but it was actually dead calm and we motored, Lake Superior like glass on the crossing from Apostles to Knife River and we were in shorts and t-shirts under the bimini staying cool. However, the next day we sailed back to the Apostles and the conditions were pretty gnarly with a double reef in the main and only a scrap of jib rolled out. We had full foul weather gear, stocking hats and gloves on and there was too much weather helm for the autopilot to handle. There were a couple of mayday calls from kayakers in the Apostles, but we were too far away to help. We sailed from Knife River to Stockton island in something like 6 hours, it was a heck of a ride.
The knife river marina is new and nice. When we were up there the water was so clear you could see the very large boulders 30 feet down. Scarred the crap out of me, I was afraid of hitting one, but I checked the guide book, and on further peering into the water it was clear that it is deep water, just very clear. I can't remember what the ramp is like at Knife River.
It was a great trip with a wide variety of conditions, but then again I'm biased, the Apostles are one of my favorite places in the world.