I have zero idea about striper fishing or using a kayak in the river but I do have some input..."typically" around July 4 they start the drawn down on Cumberland. When drawing it down to winter pool they do it very slowly over several months so there will be flow in the river in the time frame you are planning on going. I have no idea how this impact striper fishing or using a kayak in the river but just wanted to throw it out there.
Here is a link that shows the past history of water levels. Click on the years to highlight levels of the past. You can see there will be current in the river the last 1/2 of summer and most of the fall.
http://cumberland.uslakes.info/level.asp