You will need wheels
The best way to get around to the beach towns is to have your own car , scooter, or bike. After you arrive in Jose Ignacio you could walk about town but I am not sure it would be easy to get there without some means of transportation.
Local Uruguayan buses
To get to Jose Ignacio we just went out to Route 10 in La Barra, waited until the bus came that said "Jose Ignacio," flagged it down, got on and told the driver where we were going and he gave us the fare. We paid in cash on the bus. The busride took about 15-20 minutes.
We arrived in Jose Ignacio at around 11am, but the bus did not come back until 5pm!! So, we were stuck there for an unbearable amount of time with no open restaurants and miserably cold weather. But this was not the fault of the bus system. They only run twice per day I guess in the off season.