It's great you have the time! Finally I know, right?
Never been on more than a week's trip unless you include 8 days to AK, but we were moving there and camped our way up there. And like 4 years ago, out of work for 6 weeks and spent 3 of it on vacation!
We drive, ALOT. Weekend trips to Canada somewhere half the year for hockey, X country run to WI, just drove 10+ hours today with a tag trailer to pick up a new truck.
But you have a sht ton of miles packed into that itinerary. Suggest picking a few destinations only. Cannonball run to each of them so you can actually spend time at them.
Most importantly, make whatever reservations you can and then plan your trip around that. Unlikely you'll get the day you want or even a campsite at many NPs, unless there's something I'm unaware of with the Rona cancelling all the reservations form the last year and leaving them open for folks that didn't reserve well ahead of time.
To that point, plan Bs like dispersed camping and reservations at private campgrounds may get you a spot close to where you want to be when you want to be there.
On the upside, we've saved enough money with no kids sports and wife/son not driving around everywhere and the ancillary expenses, I've paid cash for a new deck and an old truck and still ahead of the game the last couple months!