A while back we moved from being a Source mod to stand-alone UDK game. This has been the best choice we have ever made, we can tell you the progression is by far faster so pictures will be uploaded.
So what we have been working with is mostly the environment, buildings, trees, street-lamp's etc. adding them into the game even before making the textures so we can work side by side with the level-design. Level-designing can be very tricky which is why we currently focusing on one great/perfect map we can cut into a smaller map for other game mode(s). The map will be maxed on our own realistic mode but also the standard team-deathmatch mode.