rear mount fuel tak

[1968aj]

I need to replace my in cab fuel tank. it looks fairly new but is leaking at sending unit and somewhere on filler tube . I filled it up and drove home and saw gas dripping under drivers door.it is not safe to drive. I know there are many threads and I read a lot of them. looking to find the latest and easiest swap. looking for info such as side or top fill and how to plumb it without 20 trips to parts store truck is a 69 swb stepside. any ideas or reference to a thread on this is appreciated.