How tough of a job is it to change the shifter bellows, I've sprung a leak in my 99 Hammer. I heard the shifter cable has to be replaced, and it's pretty labor intensive. Is it worth the $300 to have someone else do it?

It isn't hard so to speak, just takes some effort.
I've replaced all my bellows several times & it is no big deal, but for $300 I'd probably let someone else do it, especially if that price includes the cable.

I've changed mine. It's not too bad of a job. You might as well replace all the bellows if you are going to replace one.

Helps if you have the bellows spreader too.

That's kind of how I felt about it...I guess the bellows and the new cable come as a kit for about $125 and then $175 to install it...