http://www.bf1942files.com/sort.files?cat=1174&ref=1086 go there.. alot of SP mods! :D hope it helped!
I didn't make it!
You also could try a mod that works for multiplayer Co-Op mode. In Battlefield if you go to Create Game, switch the mode from Conquest to Co-Op and up the numbers of players to the max (64) that might do for a one player challenge. This way you would be hosting your own game with lots of computer players and if you aren't online you won't have to deal with people. Maybe you've tried this already, but if not it might be worth trying.