Your time frame should be OK, but I would expect that mosquitoes not have totally gone yet. I am afraid, this year, both the Sierra and Rockies will have a longer than normal mosquito season. We are all doomed to deal with the pesky critters this year! Peak mosquitoes last year were the last two weeks in July. By second week in August you would have a better probablility at avoiding mosquitoes. Hey- but first week in August is a lot better than second week in July. Just be sure you have some DEET. I have never had much trouble when walking (betweem me moving and the wind). Bigger pain is at camp so I usually get up at dawn so I can have a peaceful breakfast. Once the sun hits, the bugs really get thick.