Most solo rowers just invest in a good anchor set up. It also makes great transport to the next hole and then just wade and cast. Also, not to be a Mom but realize rowing river alone is a really big no-no in the boating world. Even slow moving rivers can eat a boat or an oar can knock you out cold. Anyway,preaching over... have fun if you do it!
My big concern would be loading and unloading 400lbs of drift boat alone. I guess with a good winch it probably not too bad? You could look at a standard floor 13ft raft too. Easier to man handle alone and transport.
My dad is the one with the boat building skills though. I'm no help there. He keeps offering to build me a drift boat but I have no place to keep the thing!