Some random comments, many years ago I dove into the study of Japanese swords for similar reasons to yours. forgotten nine tenths, so forgive the terminology.
Have you removed the tsuka? (handle) Push out the mekugi (peg) with a blunt ended chopstick or tool, and slide it off. A piece of bamboo chop stick will make a fine temporary (or permanent) replacement .
Take some close up pictures - focus on the tang ,the area under the habaki, because it is usually the cleanest, a section of blade where the temper line is clearest, and the tip. Post them up if you feel comfortable doing so.
The most important thing with any WWII sword is whether or not it is a handmade piece. You are looking for a makers signature , water tempering , and laminations. The sword will be either mass produced, hand made by an individual using traditional methods, or ancestral.
Some of the gendaito (WWII era handmade) are magnificent swords. They have the advantage of not being worn from several hundred years of use and polishing. In the last 15 years or so they have become increasingly respected.
It is very doubtful you could find the original family, unless there was documentation. Most of the swords were surrendered in Japan, dumped in a large pile, and the GI's were allowed to pick up what they wanted. If you have surrender documents , or if the sword has a family crest, or if it is the one in ten thousand with a "history" recognizable to a Japanese expert, maybe.
The most common error people make with Japanese swords is to "clean" the rust by grinding ,sanding,or filing. this puts divots in the blade which require a lot of material removal to even up. A light coat of clove oil (traditional) or clear mineral oil , to prevent further rust, would be advised.
The rust on the tang is an important evidence of age and esthetic and should NEVER be cleaned or oiled at all.[/b
The best reference site on the web seems to be unavailable, Richard Steins "Japanese Sword Index" -but there are a lot of others. Searching that phrase brought up a lot of pages with links to sites- and seemed to get rid of the "ultimate dragon fighting ninja sword" type sites that come up with some other searches.. 
You might try Fred Lohman, he seemed to focus a bit more on WWII era restoration at reasonable cost. http://www.japanese-swords.com/
"Military Swords of Japan", Fuller and Gregory is a good book.
It would be wise to do a lot of reading on the web, before taking action.
