The "crude" method will work ok. Otherwise, buy a vernier caliper at Sears for $25 and check the piston and bore sizes.

Look at the backs of the bearing shells and see if you can tell if they are standard or undersized.

Then use the vernier to measure the crank and rod bearing journals and compare to standard and undersize bearing dimensions in the manual. That will tell you where you stand and if you need to, or can, regrind. If your journals are smooth and pretty and the sizes match the specs, you may be able to pass on a regrind.

You can measure the ovality of the connecting rod big ends to see if they need reconditioning or not.

Rock the valve stems in the guides with the springs off. If they wiggle excessively then you might want to replace. Replacement guides are fairly cheap.

Check valve recession visually and by looking at the valve seats. Also you can measure the valve stem heights above the spring seats to compare.