Getting to Fos sur Mer

[cruising cockroach]

My wife and I are thinking of taking a container ship cruise to N. America later this year. The ships dock a Fos sur Mer which is located on the east bank of the Rhone when it drains into the Med. We drove by there mid February this year and the port entrance is a little isolated to say the least if one wants to get there by public transportation (or minimize taxis or shuttle services), and it looks huge once you get there.

 

Any one have any experience? I imagine Marseilles or preferably Istres is the closest one can get by public transportation.