Well Nick, I'm finding THPS3 quite easy, but having said that I still can't do better than a silver for the last two skateparks, which is getting annoying. I've got the theory for the Skater's Island on - which is rubbish IMO - but can't make it work twice out of 3 runs.
It is: skate up the halfpipe and grind the side, jump onto bent rail and grind to end, manual from that across the way onto the next rail and then jump onto the can machine and keep grinding round the corner on the wooden bar. At the end of the bar I either (a) jump off to the left and land in a manual before pulling a 540 cannonball (easiest trick with big points) on the halfpipe opposite, or (b) manual from the end and jump early onto the rail in the corner, getting the
Doorway Damage gap and allowing another manual to trick on the other side. This is very annoying because if you jump at the top of the riser you manual up, then you just fly into the wall and lose all your effort.
You have to do it a couple of times to work out where to jump. These techniques should give you a large enough single trick to make getting gold a formality. You'd think. Except I can never do this one after the other and always end up with silver. Damn!!
I'll tell you the easy way to get the Suburbia Sick Score, but be warned: it requires more manualing! From the start, grind the series of three rails, with tricks in between. Often you'll be going too fast to trick off the last one so just go straight into a manual. From your manual, jump the three pieces of board (to get the
Perfecting Your Skills gap) with a huge trick and land on a manual, continuing to a big turny trick on the halfpipe. The first time I did this I got 125,000 and just messed about for the rest of the run, making nearly 220,000. Then I did the other challenges with a huge smug grin on my face.
For the gap checklist, visit this
link. You will definitely need the perfect balance cheat for some of them, but most are easy. Not like the ones on the Outer Space Level of THPS2, which took me and my mate five hours to do, including messing about with Moon Gravity and other cheats.
PS - Bear in mind that I've got the PSX version so the gaps on mine are different. In fact, the levels are substantially different as well, but the gap checklist is for your version.