S13_Garrison (middle-bottom of Network 1B) is your friend! You'll get ~6k exp for very little work.

You will need

* ARM_INTERFACE/PUNCH_THROUGH_WALLS.aug
* A gun
* Patience


When you load into the map there is "lava" and a thin platform on the other side. Cross the lava and punch the wall on the right. Don't worry about taking damage, you won't die from touching it unless you hang around forever in it.

Once you are in, slurp up the two servers (for marginal points - this is optional but I believe it improves EXP yield) and throw one of the two blue cubes NEAR the laser. If it hits the laser you lose the mission, you just want to wave it near so when you shoot it with a weapon it will disable the laser.

(Remember, the first clip of normal ammo of a gun regenerates with every run, so you don't need to use up any resources to do this!)

Grab the orb that was protected by the lasers and sprint back through the hole in the wall for the exit. The best way to get the ball through the hole is to throw it as close to the exit as possible and then pick it up from the other side.

Completing the time objective is trivial and once you're done, skip through the menus and enter again.