My girlfriend and I will be travelling together with our 1 year old boy for 3 weeks in May from San Francisco to Salt Lake City per SUV. Rough outline of the road entails a grand loop through Yosemite NP, Nevada NP, Las Vegas and the Arizona NP's.
Since we like to be as flexible as possible in itinerary, I was wondering if there was a real need to make reservations for camp grounds in this period (7-28 May). Somewhere I have read that especially NP's get busy as from Memorial Day which is this year on the 30th and hence just after our trip. What would you recommend and do you have any other specific tips?