I would order 4 wrist pin bushings if indeed that is the failure, and do them all - they are not that expensive. A machine shop will need to install them because they have to be reamed to size after installation in the pin bore. You will also likely need a rod if the bushing has spun in the bore - a reputable machine shop will not re-use a rod like that.
You can't order rod bearings yet until you know the size of the rod journals, as the crank may have been ground in the past.
In a perfect world the piston rings would be replaced also, but there again, you'll need to know the exact bore size before you order. This cannot be measured with a tape measure, but a calipers will get you close enough. *Usually* the pistons are stamped on the top if they are indeed oversized.
The good news on the head gasket is that there is only one choice if indeed the bore is 4.2". A pan gasket and gaskets to mount the balancer and oil pump are the only other items that come to mind.