Maybe not the answer for you here, but we've found it more and more difficult to make 2 week reservations almost anywhere east of the Mississippi River. So, if the game rules shift, then we shift our camping strategy. We simply quit trying to book a spot for the 2 weeks, and sometimes, even a week. We split up campgrounds. We attempt to book the week-ends first, as they are usually harder to get. So, if we have 3 weekends, over a 2 week period, we'll book each weekend somewhere different, but still within a reasonable driving distance from each other so we can stay in the same geographical area.
Then, we see how many days before and after the week-end we can attach more days. And if we can't, then we look for different campgrounds for the middle of the week.
A couple years ago we did this approach and ended up making reservations at 5 different State Parks over a 2 week (3 week-end) trip. And actually, about 3 days at each location was just about right! One day to break camp and travel and set up camp in the new location, 1 good day to explore the area, maybe 2 days. Next day do it again.
Yes, it means setting up and then breaking camp multiple times, but in a way, there is a lot of fun in that process too!
The lesson I've learned, when the rules change, change the strategy. It works! Be flexible, and try new approaches to your camping methods. It does keep things interesting!