Doing blazer tank.. have questions, HELP!!!

[randomhero472]

i've got my tank fitted up, heading to the parts store for some hardware/fuel lines and have some questions, there are 3 other tubes/holes besides the filler hole, are all of those vents? there is one on each end that is small w/black caps on them and them one tube right below the filler neck that sticks out some.. im thinking these all have to be vents or for a FI system that requires a fuel return line... last what did you guys who've done this conversion use for a filler tube? im thinking i want to just put it in the bed, but dont know how i could get such a bend to go to the bottom of the bed, especially since i have a stepside, would it be easier to just do the marker light filler??? somebody please chime in, this is all i lack to getting the truck on the road.. thanks