Mat, if you're going to take off the caps, ie, big end & mains, check out how I did the Vauxhall engine on my article. You don't need to take out the pistons or anything, but as Geordie jim says, do replace the oil seals in the front & back of the crankcase. If the crank doesn't look worn, then you don't need to start messing about measuring it. Put new shell bearings in with plenty of clean oil all over them. Make sure you use a good torque spanner not one of these cheapo things. You don't need to change the big end/mains bolts, they can be reused. Do put new valve seals on if you have the head off, if it's not off, then you need to borrow my special tool.
I have a spare camshaft out of an injection engine, in good order that you can have if you want it.