When your on the mission where you have to find all the skaters if you go to the horse to your left there will be an opening were you go around the skate park go up there and where the grass is you will have to get off your board and walk along and you will find the skater hope this helps
First, make sure you enter in and turn on the moon gravity cheat or this won't work
The cheat is: getitup
Next, go to Vancouver get a visual on the secret tape (its over by the hockey rink,up high in the flag poles)
Then, find the glass tunnel-like thing to the right of the secret tape (if your standing in front of the hotel) then go to the glass structure and get to where it is between you and the secret tape (this is where you need moon gravity on)
Get yourself linded up with the tape then ride up to the ramp on the side of the glass structure, go up the ramp and spine transfer, you won't end up on the other side but rather on the other side of the point on the top of the structure when your make sure you don't hold down the A button but just press it as your being launched of the structure to attain the correct height to get the Secret Tape
The first old skool level is in New Jersey. At the train station there are ramps at each end. When you go up one of those ramps (if you go high enough) you get the old skool token for School 2. The second old skool level is in Hawaii.
On the sidewalk close to where the Pro is, there is a sign that says evil tiki and a tiki. If you jump into the tiki's mouth you get inside him. Gain up speed as you go down a tunnel and jump at the end to get the oldskool level, Venice.
The last old skool level is in Moscow. Find the building that says AEHNH (you can only read this at day time) and stand infront of the side with the letters(infront of the doors.)Then go to the left side. The building is made up of 5 blocks:
A light brown one, a dark brown one, another light brown one, another light brown one and another light brown one. Grind the dark brown one and jump off at the end into the window. In there you will find the last old skool level, Hanger.
In New Jersey level, go to the train station and on one of the sides on the buildings that connects the train station there is something shining, walk through it and you have just unlocked the school level from THP2!