It can all be done.
The swing arm isn't directly attached to the frame, so comes out reasonably easily once you've worked out how to stand the bike up without it. Common solutions are to use a Skylift, hang the back end of the frame off a rafter in the garage, or knock up a support to go under the engine. Which you do affects access for painting the engine, so you may want to combine two of these. You may see suggestions that you support off the footrest hangers, but they seem fragile to me, plus you may not get the swing arm spindle out past them.
Taking the frame off the engine is just two bolts, but check they move first as they can be very tight in the engine. Then there's just the matter of a few cables and pipes, but you also have to separate the carbs from the engine, so may need to take out the airbox too, and that needs the ignition system moving out of the way first. It's only held on by the two bolts, but spend some time working out exactly how you separate the ancillaries before attacking it with spanners.
Another risk when taking the frame off is that you may as well get the frame repainted as well as the engine, and then everything else looks shabby instead of having matching "patina" so the rebuild takes far longer than originally planned and costs a lot more too.
Take a look at Albie's rebuild thread as a salutary warning of where this can lead!
If you do go ahead we like lots of photo's.