I want to add a 3rd switch to control my garage lights. There are currently 2 switches, wired as I've seen in several diagrams: the 1st switch comes off the panel, then that line runs from switch #1 to the light and then finally to the last switch.

Panel --> Switch #1 ---> Light ---> Switch #2.

I figured I would simply swap that current 2nd switch (which is a 3-way of course) for a 4-way and then add a 3-way on at the end of that.

Panel --> Switch #1 ---> Light ---> Switch #2 ---> Switch #3.

The problem is that the current 2nd switch is on an old wall and I can't figure out how to fish in a new line into that wall to lead to the last switch.

So... I'm wondering if there are other wiring options for adding that 3rd switch -without- having to fish into the wall.

Panel --> Switch #1 ---> Light ---> Switch #2 ---> Switch #3.

This may be a doofus question, but I'm wondering if there is a way to wire the last 3-way switch to the -light- (which is easy to fish to) and then replace that 2nd switch as I originally intended (with a 4-way)?

Can these switches be wired in parallel and work?

Otherwise, I guess my options are: a) tear out the plaster or b) run a really long wire from Switch #1 to Switch #3 and reverse everything.

I dunno if I'm making sense, but any suggestions would be appreciated.