Yoy pay your port taxes when you book on the boat (probably be Ancona Italy, to Patras Greece) head for the main building inside the port, all the agents are in there, Superfast, Minoan, and Anek Lines are the main 3.
If you can be one of the first on the boat (the Greeks like to be last on so they are first off) you will obviously be one of the last off and it is possible to get a 24hr break in. (Ask for a discount card on boat, or ask for a clubcard membership form when you book in at the port you get 20-25% off your grub and drink, including beers)
When you land in Patras, basically, you bear left off the boat (keeping the water on your left) follow to a little set of traffic lights (every man and his dog will be pushing in to get infront of you), at the lights, go left, past shops on right, sea on left, you will eventually go round a 90 degree right hand bend, then 300yds on, you will go around another 90 degree right hand bend, there is a Silk garage (this is where i filled up all the many times i went to Greece) (oh, and the lorry wasah is brilliant and cheap!) just past that is a Shell garage (this also has a very good lorry wash), a couple of hundred yards you will go over a very bumpy level crossing.
At the top of the hill is a set of lights with a garage on the right hand corner, there is a scrap yard directly in front of you, at the lights turn left and basically keep going straight following the signs for Athens. you will after not too long come to a payage,
you pay however much it is nowadays, (it used to be 3euro 50 cents)
When you get to the second payage you drive straight thru without stopping or paying.
At the 3rd payage, you stop and pay.
When you come back, the first payage you come to you stop and pay (the other side of the road is the last one you drove thru)
the second one (where you stopped and paid heading towards Athens) you drive thru,
the 3rd payage, (which was the 2nd payage heading to Athens that you drove thru) you stop and pay,
and the last payage (ther first one you came to heading to Athens and paid at) you drive thru.
Be vary very very wary of immigrants as yo start coming into civilisation. At the lights where the scrapyard is (and where you will turn right to go back down to the boat) this is where it starts getting very very bad for immigrants, they willrun alongside you and try to get onto your motor anyway they can.
It isnt any better in the port. I have seen them hiding behind roof spoilers on lorries, trailer axles, etc etc. When you get back in the dock (same way as you went out, just look out for your boat (Superfast Minoan etc) and park near it. Then, depending on who you are shipping with, you will have to walk out the port onto the main street and find the shippers office to book back on the boat .
Its mental if you drive in Athens, 2 lane carriageways can sometimes turn into 5 lanes, there are stray dogs running around everywhere, the roads are a bit hit and miss, banana and melon sellers are common on roadsides.
Saying all that, its a lovely country to drive in!
Oh yeah, and when on the single carriageways you drive half on the hard shoulder and half on the road proper.
(Or you could ship in or out of Igoumanitsa!)
ATHINA and the yellow writing above it are the signs to follow for Athens.