First go ob by the buildings you can get into (below) Now use the invisible wall on the right to WJG up past the roof and then jump onto the roof. from here you can get on either side of the roof behind part of the wall on a ledge and if you go onto the ledge and go into skate mode wou will go into a lfg sometimes getting stuck in the rail. if you do the lfg and turn just right and hit the bouncy wall it is like a cannon/bounce to the 5th power.