I'm going the same time you are 7/17-25. It looks like the current specials run out at the end of the month, so hopefully the July specials will lower our rates. I was considering switching to Thrifty as they had a lower rate on an intermediate, but I really need something that seats six for part of my trip, there's no getting around it, so I have a Premium car booked for the same price as intermediate at National. If you don't mind using the counter or shuttle to get to Thrifty, you could try looking at them instead. They had an intermediate for 9 days for $164 total, compared to National's $239...