I'm more for taking the interior door panel off. These cars are basically 40 years old, and sometimes they just need a little TLC - which means opening things up and taking a look inside. I had a similar problem with mine and the locks needed adjusting which could only be done by removing the interior door panel.
You never know what else you may find behing there. When I pulled mine off there was a TON of greese in the door well. Looked like a previous, previous owner may have tried to lube it up with the wrong stuff.
Good luck and don't be afraid to open her up!