We and our teenagers would love to go (Still looking for an august cancelation) but we have hit Lodore already this year and are not eligible
August Lodore trips are great. Water has warmed up a touch, especially in the lower sections and there are not any bugs. We love to lay-over at Triplet falls if the beach is there (it washes away some years with the high flows). The kids love to jump off of the rock and swim in the slow water above the rapid. Plenty of trees for hammocks too.
Or take your extra day and spend the last night in Island Park. Bugs suck in the spring but August it is beautiful. Had some great sunsets at camp there and you can easily beat the wind with an early start through the rest of Island Park.