Draw bridge; Climb up either chain and jump up top.
From the Clowns Face; (read 'camp clowns face') you can jump onto a small orange ledge behind the clowns face from the clown's red hair. You can drop to the debris behind the clown's face. You can drop off of the left side of the blue rail onto the vending machines which will give you a view through a small window that watches over the orange stairs and turquoise slide inside the Funhouse.
From inside the Funhouse (go upstairs): 1. Go to the rectangular window, get in the window, look right at a blue and yellow banner, jump onto the small orange ledge at the bottom of that banner. This overlooks from the crater to the left side of the Clown's Face and the window you came out of.
FH Upstairs 2. Go to the long balcony that is wavy. Look left, jump onto similar blue/yellow banner with Orange ledge under it. This overlooks from the drawbridge to the right side of the Clown's face as well as that wavy balcony.
FH Upstairs 3. Go out onto Green Roof. Turn right, jump onto tiny brown ledge or on top of the 'container' just below that and camp behind the box. This area overlooks the rollercoaster remains and the Green Roof.
Green Roof 1; Climb up the roller coaster track there, jump on roof.
GR2; Stand under the roller coaster section and jump up onto the boxes and then the roof.
GR3; From behind the Green Roof (where the FH entrance is with the MW coin-op game), jump onto the table with the folding chair. Jump onto the stuff leaning against the back of the Green Roof, climb up top.
Roller coaster Remains 1; Starting at the Green Roof, walk down the coaster track, continue along that track until at the far end. Climb the rail next the the Roller Coaster Car. This will bring you over two humps in the track. This mainly overlooks the Green Roof.
RC Remains 2; Go to the easternmost section of the map, you will be looking at the red lizard/dragon images. Look left at the end of the broken track there. You should see white supports that form a large lower-case 'h'. Climb on the middle bar of the 'h', turn around and there will be a brown board sticking out towards you, jump on that. Stay on the rails here as the track is missing several boards. Climb up the left edge and drop onto the white boards on the side when you can't go any higher. This watches over the Roller Coaster area and has a small view of the Clown Face.
[more cheats for Call of Duty: Modern Warfare 2 here]