I use the Good Sam trip planner to plan my routes and stops. It's actually somewhat useful. It will even estimate fuel costs for you. Try it.
I always make reservations, especially for the holiday and special event weekends when the parks are likely to be fully booked. It's one less thing to worry about when on the road. I usually plan to stay at least two nights at each park. That way I have a bit of schedule slack to work with in case I have to shift reservations around. Works for us.
rvparkreviews and VPN are your friends