The fuel pump is under the car on the drivers side under the rear seat. the fuel pump relay is under the foot kick pad on the passenger side, white in color and usually hanging on a bracket.
This depends upon the model and year. Wagons have the tank accessible under the back of the car, behind the rear axle. On early 240 wagons, the fuel tank is held by 8 or 10 large bolts and if you are careful to detach the fuel pump bracket on the driver (left) side, the bolts can be removed and the tank can be lowered. I recommend a floor jack to lower the tank without damaging it or ripping the sender wires out of the top.
Coupes and sedans are a different story entirely, most wagons should be similar although some may have additional mounting hardware or other components that need to be uninstalled before the tank can be lowered out.