Rering ??????

I have a few questions. I have been thinking about rering my 318. I looked at the cylinders and they look good. Of course I haven't checked the cylinders with a micrometer but I can still see the hone marks on the walls, I don't see any gouges in the cylinders. I know I should take measurements to be on the safe side. I have the book How to rebuild small block Mopars and they do it in two ways, one using an inside micrometer and the other ring and feller gauge to check tapper. Which would you guys recommend? I haven't priced an inside micrometer but how much do they run?

Do I need to pull the pistons to check tapper? If the walls are ok should I assume the crank would be in good shape too? Or should I plastigauge it anyway? I think I already know what the answers are going to be. Also, there is some light surface rust on cylinders walls but everything turns freely, do I need to hone the walls?

It's an 86 318 and has a roller cam and lifters. If I put in a flat tappet cam and lifters I don't need the girdle for the lifters correct? I think I am going to build something mild for now. I have a Holley 3310 600 CFM and a 4160 750 CFM both vac sec. What would be a good mild cam and intake for it? I think I may leave the heads stock for now.