2002 31' with Aluminum tanks

I'm doing some prep work for the upcoming fishing season. One thing on my hit list is to get the fuel tank levels on the NMEA2K network and calibrated properly. I pulled the lids in the deck after getting no resistance on the wires under the helm to find that there are no wires run to the sending unit. No big deal, I can run the wires but I can't for the life of me figure out how to get the wires from the top of the tank, under the deck, and onward to an accessible area to then run the wire forward. Anyone know the best way to route the sending unit wire under the deck and on top of the tank?

Thanks in advance for any help.