GET 14K IN UNDER 1 MINUTE!!!!!
This is the easiest and fastest possible way of farming skill points
The best thing about it is that you don't have to kill enemies and you can't die
Load up Jake, Chapter 4, Stage 4-3 on No Hope difficulty (this difficulty gives you x2 the points)
Run through the street, until you encounter the 2nd barricade
Jump over it and look to your left, open the chest to pick up the 2000 points
Run a little further, and look to your right behind a garbage container
Open the chest to pick up the 5000 points
Jump over the 3rd barricade and open the door
When the next area is loaded, the game will be saved so just quit and repeat
This takes under 1 minute and grants you 14k every time ...