Downriver Canoe Company, based in Bentonville, is the outfitter that promotes aqua blazing. On Mondays they run trips that begin at Port Republic, north to the VA/WV border. They will pickup as far south as Waynesboro.
The Virginia-based outfitters do not go all the way to Harpers Ferry, because WV has very strict and high-dollar licensing provisions. The best they can do is get you to the VA/WV border (roughly Rt. 7) where you have to get to a phone, call them, and they’ll pick up their gear and drive you someplace nearby–usually to the A.T. Then, you hike into Harpers Ferry. (Theoretically you could get a WV outfitter to meet you at Rt. 7 so you could take their canoe to HF, but the logistics are a nightmare.)
There are places along the north-flowing Shenandoah River where you cannot paddle or float, in any year, due to dams and other obstructions. Near Front Royal you have to portage a couple of miles around some (put all of you gear into the canoe or kayak, then CARRY it to the next put-in). In a low-water year, portages are even more frequent.
Unless you are a very strong paddler, taking the river to the WV border usually takes longer than it takes a seasoned thru-hiker to walk there. And if you are relying solely on the river flow so you can float there effortlessly, it will take a LOT longer.
There are some legal places along the river to camp. The outfitter should provide a map showing various points of interest, including where to camp and where not to camp.
Skyline