Here's a tiny ugly patch to make xpdf remember positions in files and restore them. You open a PDF document, read it a bit, then quit xpdf. Next time you open the same file, the same page will be shown as it was when you quit.

The positions are stored in ~/.xpdf.bookmarks.

If you are using xpdf from FreeBSD ports, just put the patches into /usr/ports/graphics/xpdf/files directory and rebuild.

Patch 1
Patch 2