I go most years the second half of August. You will have no problems. Some stay at the pass all day, we don't we do our morning rides, rope drop to 2 and then go take a nap, relax and go back in the parks, we see F!, WOC or fireworks. Because a lot of kids are heading back to school and most people took there summer vacations we find the park is really like the end of April or May. A 4 to 6 level, even with the APs coming back in. Also the first hour is golden if you are staying on site, because at DCA no one but those on site and get in, and also on other days at DL only a few have mm, because they are all APs coming for the day, that also works a lot in evenings, where the park empties out after 10 or 10:30 and it is far less crowded in the evenings. I have been also every month, I think I missed july and October (which is on my list this year), and to me one of the best times to go is August, everything is open, shows are all playing and crowds are fairly low. With a good plan you will do everything more than once and have a great time.