Keith, You should be able to go nearly all the way to the end of the threads on the shock body.
Its very easy to remove subframe; Remove seat, release springs that hold silencer to pipe, loosen hose clamp where air box boot fits to carb, take out (4) subframe bolts, and the whole thing comes off in one peice with fender, airbox, and silencer still attached. Now it is much easier to access the shock and check upper and lower shock mounts for wear.
If you are near the end of the threads on the shock body, time to get a new spring, and if thats the case, for an extra 50-60 bucks, send it out to have it revalved and resprung.