I would check for 1.2 volts DC on the green wire in the PMD harness while cranking the engine. That will tell you if the PCM is commanding fuel or not. I agree with also checking the shutoff solenoid and grounds, and make sure you aren't getting any air in the system.
Im new here, but just wanted to say I have enjoyed reading your thread. I really like seeing people use their trucks for work and hauling. I have to agree with running 3rd gear towing. These engines really like some RPM in my opinion, much different than my 94 cummins, but I enjoy driving both.