Post the questions over on
Welcome Plenty of reading over there on this subject set.
My first thought would be Mobil DELVAC 5W-40 for the engine. And a low-restriction, high-capacity oil filter (DONALDSON Synteq media; same as AMSOIL EaO). Same brands for air filter.
Also look at Auto-Rx regimen for that truck,
first, using dino in 5W or 10W-30 with cheap filters. A series of UOA's would be best to document and see wear-trending.
Since you intend to do some towing I'd also look to being perfectionistic about the cooling system as in
all new parts. I've never been sorry to do it that way as repairing component-by-component is a PITA. De-ionized water with FLEETGUARD Compleat is my choice, and a ROBERTSHAW Balanced Sleeve thermostat (Mr. Gasket), not to mention new fan clutch and any possible improvements to the fan shroud. Age, alone, dictates this level of work, IMO. Removing block drains is the first step. I usually run either RMI-25 or Schaeffer's #258 afterwards.
Also a good time to replace timing chain if so equipped.
As to greases, contact via PM "Sales Rep" [?] the SCHAEFFER Oil rep who posts there.