After reading numerous threads about chains, cleaning chains, replacing chains, etc... I went to the LBS earlier today and talked to them about my old C&V '85 Fuji Del Rey and how I tried cleaning the chain, but it's old and worn, and I might as well take the plunge and replace it.
The LBS had 100 gazillion types of chains, most are for high tech index shifting, 9 or 10 speed STI shifters. They redirected me to another LBS that has more "old school" stock inventory.
Long story short, I showed the guy at the counter a picture of my old Fuji on my smartphone. He said, "Oh cool man, that's a classic! You got down tube shifters... Suntour components... 12 speed... Not a problem, gotcha covered right here."
He handed me a KMC Z33 box and a Park Tool CT-5 mini chain tool, Grand total cost: $18 bucks (with discount coupon). He explained about removing my old chain, lining up the new chain to the old one, and popping off a few links from the new one (116L down to 112L), and carefully threading it back on.
Thank you all for the terrific help! The new chain went on with ease, no problems at all. I would have liked one of the better chains but they had me stick with the Z33 for non-index shifters. Okay, whatever, it works and was cheaper in the long run.
I shifted up to the largest cog (30T on the rear) and the large 52T chainring to make sure the Suntour derailleur wasn't stretched out, then shifted back to the smaller 42T chainring (as seen when the photo was taken). 112 chain length is right on the money. It's not sagging and it's not stretched out.
You all are the best! Thanks again!