You could also just install sliding door contacts as well.  A lot less
work, and they look pretty trick.  I just finished putting in my power
locks on my '84 (thanks autodax.com) in the front and will be wiring my
sliding door in a week or so.  I'm doing contacts so I might post a
writeup later if anyone is interested.  I was beginning to wonder if my
Westy was the only one getting all the fun amenities done (people always
laugh when they find out my lovely '84 POS has power locks, remote
starting, alarm, a killer stereo, and soon will likely have power windows.

-Nate
'84 Westy