Traveling around Luxor Questions

Going to Egypt in early August (I know, it'll be freakishly hot, but it was the best timing for a bunch of reasons). During that time, we will be in Luxor for three days, visiting Karnak, Valleys of the Kings/Queens, etc. How would people recommend getting around? Should we hire tour guides to take us around, or are there a lot of modes of transport that we can use to get to the various sights?

Going off of that, in the Valleys of Kings/Queens, do you walk from tomb to tomb? Or will we need drivers/bikes/buses?

Any help would be greatly appreciated. Thanks!