Priest has a few decent bank access areas. Smith Springs recreation area isn't bad - walk around the cove to the far bank across the boat ramp and you can get to some decent water. If I remember correctly, you can get to some good areas around Long Hunter park as well. Since the lake is drawn down right now, you can walk the shoreline pretty well.
On the other hand, Priest can be a tough lake in my opinion if you only have one day to fish it. It took me a bit of trial and error before I had much success. Your odds of catching some fish probably will be better with a guide. Plus, fishing out of a boat will get you to a lot of places that you won't reach from the bank.
Check out www.tennesseebassguides.com if you decide to hire a guide for a half day trip.