A big part of the GeoCities content has been available as a torrent file from a group called the Archive Team and maybe you can still download it:

http://archiveteam.org/index.php?title=GeoCities

The file was huge, about several hundred gigabyte. I didn't download it, because I don't have enough space and downloading it would take ages with my slow connection.

On http://reocities.com/ you can browse through some of the old pages and sites, but many things are broken now, missing images.