Tulcea is a city in Romania, the starting point of Danube delta.
From the center near the port, take bus number 3. (You can buy a ticket in the ticket machine or in a shop with the sign Bilet. If there is a ticket inspector and you have not validated the ticket after you entered the bus, you might have problems.) The bus follows the main road, then turns left and after that returns to the main road towards Galati. Get off the next stop (after the bridge). You are at a junction where all traffic from Tulcea and Constanta passes.
South towards Constantai
There is a *very* popular HH spot right at the Petrom gas station, at the intersection of E87 and 22G. To get there, just walk along Strada Babadag up (to the south-south-west). We had to compete with numerous locals (we counted more than 15 in half an hour) to get a lift. Locals seem to all pay for the lift (we did not, without saying anything). Had a lift to Constanta in 40'.
From the East
Coming from the East and Northeast (Brașov, Cluj-Napoca, etc.) you will have to take a ferry across the Danube in either Galaţi or Brăila. Hitchhiking across is possible. All the trucks go through Galaţi because the Brăila ferry is too small for them. However, waiting times appear to be much longer in Galaţi, but this might not be relevant to hitchhikers.
There is a park at the lake in the city center, right next to the indoor swimming-pool, where you can camp. It's also very close to the port (about 500m).