Although I honestly believe that Harley doesn't mind all the requests for the 66 instructions, I thought I'd offer a little info I learned about the Remington Nylons (after I too got the manual from Harley).
There's a yahoo group called "nylonrifles." If you join it, they have a number of "files" available online, including .pdfs of articles about these guns, tear down instructions, parts suppliers, tips to cleaning and repair, etc. It just doesn't cover the 66 either but all the nylons--e.g., 76, 10, 11, 12, etc. Worth checking out if you're in the hunt for some specific piece of information.
On behalf of all of us nylon 66 owners who have received the instructions from Harley, here's to ya! Thanks. You gave us that hope we needed after we each brazenly (a/k/a stupidly) tore our rifles down before we knew exactly what the heck we were doing. You saved us all when we each thought we'd done the unspeakable -- permanently ended the life of a favorite plinker. Please don't take my post here recommending another source of information the wrong way. I'm confident you'll still be the go-to guy for lots of future nylon owners as the FiringLine is a great site. Maybe this will let you take a little, well-deserved breather for awhile though--at least from the nylon guys.