How can I get copies of library of congress's archival manuscripts? I require photocopies of "Archival Manuscript/Mixed Formats" from the Library of Congress. They have a collection from one author which has otherwise unpublished technical documents that are very relevant to my area of expertise. Judging by the indicies, there are at least 20 boxes (out of 106) that are relevant. None of these are digitized and most are very technical documents with information not seen by people in my field.

I'm not sure the best way to attack this problem because travelling there is far from where I live now (6 hrs by plane) and the librarian I spoke on the phone with didn't think that our library could request it. LoC seems very restrictive about working with their material, that is they won't let me personally go the stacks and browse the boxes, and they say they only allow 5 books to be reviewed at a time.

Are there any tips or alternative ways to get the materials? Our research team is rather large for an academic team, so would it be worthwhile to ask a Congressperson to request it on our behalf? Just looking for input.
This is not an answer, but too long for a comment.

I used to live around Washington DC metro area. I went to Library of Congress very often. They don't have open shelf policy. You sit in one of their reading rooms and pick a desk. You request for materials to read. The librarian will find them and put on a cart. Somebody moves the cart out to the desk you sit. After you finish, they'll put them back to the shelf. I never checked out books from them. Don't know their check out policy.

I remember there was a certain limit number of books for the request. 5 seems to be correct because you can only load a certain number of books on the cart.

It is definitely worth while to ask a Congressperson to help if you live in the US. But, it sounds like it's worth making a trip there to examine everything they have. 106 boxes is a lot. It takes half a container. I am afraid no libray is willing to take such a huge task - I assume you're thinking of inter-library loan. My 2 cents.