Start at the one end of the maps spawn point. The one where you are behind the red building with the yellow tractor inside. There is a hill and rocks on your right.

From that spawn, stay right as you go past the rocks, go down onto the catwalk to your right. There are several grey crates piled in the one corner of the catwalk.

Throw 2 CPs (CP and SG) into the little space between the bottom boxes, this will trap the cp grenades in the apropriate spot.

Theoretically, both CPs will land on top of the grey boxes. If this happens, climb them and jump onto the hill, as high as you can.

You are now out of the map. You can get behind your spawn or climb the sniper tower there, but you can't get to the top of it/invisible barrier.

Have fun offline with this, remember that you can get spectated in theater mode and banned for cheating.