Well, I just used the whole entire map pack but I could help you out with just ripping them (I guess... I have a fair bit of an idea on how to do it but it would take some time because I haven't tried to rip them before). It's pretty simple though, remove the spawn values in the all.spawn for the level changers, get rid of the other maps totally and you are done (With a little bit extra but yeah).
Ex modder, Zones only ferret and will someday release a game (Resident)
On forum: 02/20/2010
I have a tutorial on porting levels between games, just have to find it and send it over. You'll need to get the levels from the Super Map Pack for it to work without problems though.
The tut assumes that you work with acdc tool though. Working with the SDK is easier though. Its just the compiling.
Alternatively, you could work on the levels in the SDK (spawn wise) and then use my tut to link them to your existing all.spawn and game.graph.