Here's the map pack of all the community maps running on the RTO Killing Floor server. Download it here: https://www.sugarsync.com/pf/D8809808_66097902_455563

To install:

1) Unrar the file to a folder like C:\Mappack
2) Go to the folder you unrar'd the file to and you will see 4 folders (Maps / Textures / System / StaticMeshes)
3) Locate your Killing floor folder in your steam directory. This is usually under C:\Program Files (x86)\Steam\steamapps\common\killingfloor\
4) Notice your killingfloor folder includes those same subfolders (Maps / Textures, etc)
5) Move or copy the files from the RTO map pack subfolders to the their counterparts in your killingfloor folder. The files in the maps subfolder should go in the maps subfolder of the killingfloor folder etc.
6) Be sure to do all 4 subfolders so that all the maps work
7) Launch KF, join the RTO server, and start killing zombies

Any questions, just ask!