Ok mechanical gauge so it is probably reading true over tempature.
If you want to go cheap I'd do the oil pump and while you have the pan off pull at least one of the main caps just to see what kind of shape the mains are in. With 150K showing you should have gone with the whole works, guess it depends on if you just want it to last a little while longer or another 150K.
For future note, for all the trouble you have to go to pull the pan in most vehicals it's cheap insurance to replace the oil pump if you have the pan off...
As for changing the bearings, it probably could be done, maybe, in the truck but it would for sure be a lot easier with the engine out!