Are you cave diving? Never dove Ginnie before? Eh...follow your training and the lines in the cave. Spend time staring at the map in the shop before and after and figure out where the main line goes on the map. Hard to tell you what to look for if you don't know the catacombs from the park bench or the ear from the eye, but once you have a few landmarks down its easy to explain where the Gizzard or Toxic Waste Tunnel is...
He said he wasn't cave trained. I think the best advice was the Ginnie basin with precautions about the ballroom,or the Devil's spring run.