If you are in no hurry and have it lying around, soak the rusty parts in Evaporust. It'll remove the rust from your drums enabling you to simply Scotch Brite the surface. A soft wire wheel will work quick and easy if you have one.
I'll probably be doing that, I've got the time so I'll look into that today.
Here's some more pictures of the light rust on some of the parts I've got.
That last picture just had some loose rust gunk, wipe off but it looks like this must have sat for a while so the bottom of each drum got something in it. I'll see if I can put every part into the Evaporust and leave it for a day, see how it goes.
I checked out the clutch plates in the direct and forward drums, and they seem like they are pretty unused, the few grooves they have are pretty pronounced. One of them had some wear inside of the groove, but other than that anomaly they were all the same.
One thing I did notice as well was that my direct drum has a lot of space between the pressure plate and the snap ring that holds it all there. From the video I was watching they said about .015" per clutch plate, so with my 5 plates it should be .075". I didn't bust out the feeler gauges but this looked much too large.