Inherited extensive Civil War book collection - I'm lost

My late father sold his Civil War book business about 25 years ago. Before he sold off his inventory, he cherry picked most of the best stuff to put in his collection, which was already substantial. By the time he realized that none of the family wanted the books, he was too old to ably sell them himself. So they sat. Now they're mine, and I'm not quite sure how to proceed. If they were run-of-the-mill titles, I'd give them to a library or university. There are about 70 boxes of books, with many, many quite valuable titles (or so he told me). He also has a bunch of limited edition prints, maps, letters, and other paper.

My biggest issue is that he never inventoried them, so I'm unable to discuss this in detail. The books were stored in his personal library on shelves behind smoked glass, so I can vouch for the care they've received. We had to sell the house, so I packed the books and moved them to a climate-controlled storage facility. I can take the time to inventory them myself, but have no eye for the things that would make them particularly valuable (I can do titles and edition #, but I am ripe to overlook some good details). I know there are some big dealers out there (my dad new a bunch of those guys, but they're almost all retired or passed), but I feel I'm at a horrible disadvantage in negotiating a sale without a detailed inventory -- including valuations. I'm not inclined to have them appraised, simply because of the volume. FWIW, this is all happening on the East coast.

Any wisdom/direction to share? Thanks all very kindly.