We come to CB for 3-4 weeks every summer. We're currently on our last week of a 3 week trip. Late July-early August will mean just about any hiking trail in the area will be accessible because the snow will have all melted. We've done a couple high elevation hikes that were a little muddy, but not too bad. The rivers are running pretty low, which means in 3-4 weeks will be even lower. But there is still good fishing to be had.
If you are a hiker, I could fill your week with nothing but hiking suggestions. If anyone in your family likes to mountain bike, I can tell you all the good trails. The mountain itself has incredible downhill trails. There are bike jumps in town and a skate park where bikes are welcome. My boys and I can kill an entire afternoon at those 2 spots. If you like to disc golf, there's a course on the mountain.
Will you be in an SUV with 4WD or AWD? That will change some of my suggestions as far as hiking is concerned.
If you have a SUP, that opens up more possibilities as well.
Lots of places around here to sit with a cold beer and enjoy an unbelievable view.