Sorell is 26 km from central Hobart — about 30 minutes by car along the Tasman Highway (A3). Kinetic buses run hourly between Sorell and Hobart (around 40 minutes, very cheap), departing from the Hobart city centre and stopping in Sorell's town centre. If you're driving from Hobart Airport, Sorell is just 10 minutes further east along the same highway.
Sorell also sits at the junction of the Tasman Highway and the Arthur Highway, which makes it the natural last stop before heading south onto the Tasman Peninsula toward Dunalley and Port Arthur. Fill up with fuel here if you're continuing south.