You can refurbish the clutch pretty easily, without taking other stuff apart. The manual for your bike is elsewhere on this site. If that doesn't resolve your problem, you may be looking at something in the transmission. Getting that far into it calls for removing the engine from the frame, pulling the head and cylinder jugs, and cracking the case halves.
Beware of "as long as we're here" mode. Anything that looks suspect should be replaced, since you're essentially pulling the whole engine apart, and it's a LOT of work getting it apart and back together (as you suspected).
I'd try the clutch route first. Cheaper and easier than pulling the engine, and may (I repeat MAY) fix your problem. Good luck, and let us know how it goes.
Luke M
Used to have a 1979 CB750L, sold it as a parts bike, now riding a slightly modified 1984 VT700C. Network/Field Engineer. Central OH, USA, Earth, Sol System, Milky Way Galaxy, Universe.