Grab a can of pb blaster and soak the fittings on the fuel filter.
Since you have zero fuel pressure it is best since you state power out of the relay to then go to the connector for the fuel pump. Yes you can access it without dropping the tank, check for power there and chances are you have power and good ground there, after this if found good then when you turn key on if you cannot hear the fuel pump then remove gas cap and listen for it to run about 3 secs then turn off. You will then have to drop the tank and change the pump if you are getting good power and ground to the pump but is not working.
yes it will be on the side or top of the frame rail right at the tank.
Sometimes it is just as easy to remove the bed to service the pump, sometimes not.