CHEATS WORK AND MAKE THIS EASY AS CAKE!
Something that would normally take people days if not give up on trying to do it entirely can be completed in probably about half a hour.
Load up your desired challenge and then hit the escape key and go to settings/options turn on the Developer Console. This is a one time step, Console should stay on even if you quit out of the game.
Now get back to the game and hit the ` key (tilde key, the one above the Tab key).
Now enter "sv_cheats 1" and then enter "noclip" (both without the quotes). The first thing allows you to use cheats and the second allows you to both fly and go through things. Now fly yourself to the end of the chamber but don't go on the elevator.
Hit the ` key again and re-enter "noclip" and "sv_cheats 1".
Next create a manual save.
Next his Escape key to bring up the main menu and then select "New Game" and then start a new game. The second you start hearing audio go ahead and hit Escape key again and then go re-load whatever challenge you were working (not from your save, load from scratch) and now after that loads up then you load up your challenge save.
Now go on the elevator and you should see the Steam tracker pop up in the corner.
Rinse and repeat till you have everything gold.
Not doing the whole new game process will have the game know that you used cheats, new game wipes that information. You would think they could easily patch that but luckily they haven't.
Small notes.
In Test Chamber 13 the requirements for gold are very small so for the steps/time related ones get yourself as close as possible and waste as little as much time as possible.
Test Chamber 16 is the one with all the turrets, while normally not a problem as you just bypass everything one turret will be at the very end and can shoot you in front of the elevator so angle yourself towards the left of the elevator doorway as possible but don't get yourself stuck in the floor or wall as after you turn off the noclip that can happen. Just saving you time from having to waste on reloads.