Scan them at a very high resolutions.
300 dpi might be good. 600 dpi if you think you might want to print them later.
Then burn those images to DVDs.
I think mounting them on acid free paper is overkill unless you intend to frame them.
Your photos won't fox like old books do, incidently.
The paper they're printed on is very different than the paper that books and magazines are printed of. There's no acid in it, hence no foxing.
FYI, I make Rosetta's images on a Epson 15000, working that Epson scanning software in conjunction with PhotoShop.
One of the features of PShop is an routine that will make your collection ready to publish on line, incidently.
If course if you publish them on a website, you'll first want to reduce the dpi of the images (assuming you've archived them at high resolutions) so that they can viewed on the screen.
72 dpi will give you images on the screen at about the same size as the photo you scanned.
Higher dpi's (online) will make the image appear larger on the computer screen and give you a much higher resolution image, too.
Archiving collections like these is not really a difficult task if you have the hardware and software.