Just popping in with some observations from my August (15th-20th) rental, since you guys are getting close.
I haven't read thru all of your posts, but my experience was that rates from 6 months out to even inside a month out didn't really change all that much, and in some cases even went up. My advice has always been to check occasionally, then once inside 3 weeks or so out, check pretty much daily. This time, there was some small movement once the 2 week mark hit, but I did best from about 7 days to about 3 days before the rental.
Like many of you, I prefer an onsite rental that allows me to skip the counter and choosing from a row is a nice feature too. Alamo is the obvious choice, but some of the others are getting more flexible with that, especially if you join their insiders/rewards/gold, etc. programs, which are generally free.
Alamo didn't work out for me this time. I think the best I could do was about $179 total for an intermediate for the 6 days using a Costco discount along with a $25 off coupon. That rate hit about 10 days before the rental and wouldn't budge. Surprisingly, and for the second trip in a row, Hertz was the winner for me. Using a AAA discount and a $5/day off coupon, my final total was about $136 total for a standard. I received an email from Hertz the day before saying to head straight to the garage and I could pick from anything in the "gold" row. Chose a Nissan Rogue and was very pleased with it.
Note that the Hertz discounts didn't really kick in until that last week. Alamo is probably still my preferred agency, but the Hertz experience has worked well for me the past two trips (and their platepass policy is very similar to Alamo (I think $1 more per day that you use it)...be careful with Budget, Dollar, etc. on that.
Anyway, keep the faith, your rates should start going down pretty soon and good luck!