As has Hank reccomended I would lube the cylinders, check compression and prime the oil system (after changing the oil and filter).
However I would go one furhter than Bruce reccomends (since you have it out of the truck) and replace all the gaskets now just for GP.
Definetly at least the front and rear main seals as Bruce reccomends.
If you don't mind working with tube 'o gasket, the Right Stuff brand has been much better to me than any other, it not only seems to seal the best, but when it comes time to take it apart it doesn't seem to take as much force ont he putty knife / gasket scraper to get the pieces apart so I expect there's less of a chance of warping anything.
If you choose to replace the gaskets, clean up whatever you can while you have the covers off, if you have it on a rotisserie have a look at the cam lobes (engine upside down).
You might pull a rod cap or two and check the bearings while you're at it, I would, but that's me. That recently saved me some cash on a bent 8 I have in a truck. I pulled the pan and a rod cap when it started fouling a cylinder with oil, even with good compression in that cylinder still. Bearing was scuffed, one spot was gouged with the copper showing. It still was showing good oil pressure, but I don't know for how much longer. At this point it would appear all I have to do is grind the crank and change the bearings (and the cam, damn new low zinc oil anyway
).
Sory if that seems like a rant but I figure you might want to check (and if the cam looks good, you might put some slicum on the lobes for the inital startup after all this.
FWIW it won't help it start, but you might want to try and rinse out the cooling jackets while you have it out.
That and it might look good with some fresh paint if you haven't doen that already.