I remember Sonora. I stopped at a little meat-and-three diner there. Because I looked so pathetic and voracious they just kept bringing more food and piling it on my plate. Did not see the round house either, though.
I would recommend riding to Florence, OR and catching some extra miles on the coast highway; the section from Florence to where you meet up with the TA again is awesome. Admittedly, it might be less fun northbound riding on the side of the road away from the coast. No map needed other than a state map. Most of the state parks along the coast have bike-n-hike camping sections.