I would have thought a month and 100 hours would be enough to fly across from Florida to the West Coast - now that'd be a real adventure. Can't be more than 2500 miles along the South coast and through Texas to somewhere like Southern Arizona where many of the boneyards are. Eight 3-hour legs over, say 12 days, same time for the return journey, and a week in hand for weather delays? Just an idea.
As a keen aviation photographer, I've been to some of what pass for 'boneyards' in Florida. No huge areas filled with hundreds of retired aircraft unfortunatley (or fortunatley, depend how you look at it), but many of the samller regional airports are final resting place to many an old DC3, Convair, Electra, 727 and DC8 as well as many operational ones too. Try Opa Locka (KOPF) near Miami to start with. Also quite a few derelict aircraft at Naples (KAPF) last time I was there. I would imagine that a pilot landing at these airfields would stand a much better chance of being able to wonder around and look at/photograph the aircraft than at, say, Marana or Mohave.
The best thing to do is go on !!!!!!!!!!!!!! and search for each airport you plan to visit to see what's there.