Basically look for the bars coming from Ft McAllister toward Hells Gate. Be EXTRA sure to follow the markers through Hells Gate, it is a huge mud flat with a NARROW channel through it.
Once past Hells Gate, you have a lot of options depending on the weather and or tides.
Option 1 would be to go straight to the R"12" marker (note the sandbar to the north of it) then to the R"10" (note the bar to the south of it) and on to the G"9" and G"7" can (also note the bar South of these two cans). Cut due North from the G"7" to the Southern tip of Wassaw (note the narrow channel and bar at the mouth of the Odingsell River.
Option 2 would be to go to shoot ENE to the channel between the bar at the R"12" marker and the bar that dumps out at Delegal Creek toward Adams Creek. Keeping in deeper water but well away from the shallow water of the bars in Ossabaw Sound and Little Wassaw/Pine Island flats, on to the G"7" can and then Odingsell.
Option 3, if the sound is very rough, take Adams Creek (note the mud flat just before it), then to Odingsell, up to Wassaw Creek.
Once in Wassaw Creek it will be the first dock you come to.
Best thing to do, is plan a day to run each of these routes so you can get familiar with them depending on the situation needed.
Forgot option 4.
You could forego all of these and run straight to Bradley Point down the South Channel, then all the way to the R"4" bouy, then cut to the G"5" and G"7" cans, to Odinsell. IF the waves ain't bad, they usually are.