Sometimes the best deals can be booked months in advance; other times the best deals appear at the last minute. What I would do in a situation like this is book a refundable rate now via each hotel's website. That guarantees you have a place to stay and lets you plan your budget. Then, check back every month or so to see if a better rate is available. A few days to a week before your stay try the bidding sites like Priceline as hotels often dump excess inventory at the last minute.
Also, I recommend you check in the forums for the states and cities you're visiting for tips on where (what part of the city/area) to stay and how much is reasonable to pay.