If the motor has never been apart, i would save the grief by rebuilding it, especially if you are going to effort of making it right look right.
Painting is easier if pulled apart i guess. The barrel will be bare. Head painted same as cases.
Paint stripper etc is the hard way to get the old paint off as it seems to stick big time to the cases. I have given gunter some cases to water blast this time to see how that goes (obviously better as i'm not doing the hard yards cleaning).
Rebuild, go for new rod, gudgen pin and little end, new set of mains/gearbox bearings, etc. and it will last a long while. Top end will need checking, and if within spec a hone maybe, or start fresh on the next oversize.
Carby - new slide, needle jet and needle for the Bing to cure any issues there.
All depends on what you want from it? a Show room looker, or a fully functional bike that will last.