We entered John from the Royal River last month. Stayed 2 nights on John. We felt lucky to grab a site late afternoon, with 2/3 full. Our 2nd night I think one site sat open, and the other had turned over. I'd say it's just luck/timing, and as always, earlier search ups the odds. East and West Pike were sparsely occupied, much to our surprise. If you end up going up the Royal River, the portage into N. Fowl ... well, you will either need to walk IN the river and line your canoe, or bushwhack, to get to actual floatable water from the "end" of the portage.
I was on John numerous times when my kids were little. Never had a problem getting a site. East Pike is a really nice lake. In my experience, the campsites were more apt to be filled there than on John. West Pike is another great lake with more site options. If you like portaging, going from John to West Pike isn't too big a deal. From John, you can also explore the Royal River. I've never had to portage from the put-in to John (or vice versa), but I've never been there when the water was this low.
You could go from John to east pike. It’s a longish portage but very pretty. East pike is beautiful, esp In the fall. You might not see anyone!
I have this sneaking suspicion that although there is only one permit per day that I may find all three sites taken. Preparing myself accordingly anyway for that potential. Any fishing/exploring advice or alternate plans before I go in? Is there even a portage from the entry point to the campsites? I like to portage so I am thinking of snagging a permit for Lizz/Swamp instead. Or should I stick with John Lake? Thoughts are appreciated.