c1000mg,
Although I'm not using that many products with cataloger, I can give you some answers. You have allready seen that you have to make a page for every (sub)category and product. There is no way around this situation. There is currently no option to import data. For the text this would not be al to hard since it will be preparing information from the existing system to SQL that can be used in the database for CMSMS (think of this as restoring a backup of the contents table).
The available information can be located at:
http://wiki.cmsmadesimple.org/index.php/User_Handbook/Admin_Panel/Extensions/Cataloger (which is the same as pressing the help button in the module).
If you have some php knowledge you migth first try to generate that many pages automatically by using coding that can be found in:
http://forum.cmsmadesimple.org/index.php/topic,2180.msg11839.html#msg11839. Be careful, since it has been posted in early stages and the tables might have more columns and the logic behind the pages/content might request for more information with the more current versions of CMSMS.
[edit:]It is probably better to look at the original thread of this message, since it includes discussion on modern versions as well and how to use it:
http://forum.cmsmadesimple.org/index.php/topic,15369.msg76304.html#msg76304[/edit]
You don't mention the loading of the images? The loading is something that can be done easily with ftp, but connecting them to the correct content, might give some headaches. :-\
Duketown