I replaced my in tank fuel pump last summer. Pretty easy, although it takes a couple of guys with a couple of screwdrivers (and a few strong words) to get the cap off of the tank. The way to tell if it's the in tank- you can hear a high pitched whirring sound when you put your ear to the fuel inlet if the pump is functional. The symptoms that it's gone south:She will lurch and sputter when very hot. Not really the symptoms you are describing. I would start with the relay if I were you, find it, re-solder (or replace it) and see if she runs. If not, move on to the pump.

I always try to start with the quickest,least expensive problem first.

Good luck.