Bob, you're a better man than I (so to speak): I've been intending to get to my Dad's stuff for years. Life does get in the way of plans sometimes, doesn't it? But this is really worth doing, so keep up the good example!

I think you'll find all of the archival boxes you need at Highsmith, a company that specializes in selling library materials. Even if you don't end up with an exact box per reel, you could at least keep a few at a time in an archival box.

We had an archival specialist at UTA who, in addition to rebinding books, built beautiful boxes for rare and fragile books--these are called "Library of Congress boxes." LC boxes are "for brittle books until they decide what is the next step," (this is a quote from an article I wrote about her work a few years ago). You may be able to find at a local library a book called Boxes for the Protection of Rare Books: Their Design and Construction, Library of Congress number LC 1.2:B69. This book is available through Google Books, there are several "snippet" views, but there is also a full copy of it (you would read it through the Google viewer or maybe as a PDF).

These boxes can be made any size, and you could easily make them the right size for tapes. In the long run, you want the tapes to be safe, and you could probably make these several at a time.

SRS (daughter of a librarian)