I am also very close to the Crash 1 platinum. I spent almost two hours in total to get the gold saphire on the two bridge levels "Road to Nowhere" and "High Road".
Honestly, most of the time I just rush too much and try to sprint more than needed for gold. I end up dying a lot, but getting gold or better first time I make it to the end.
I really hate long levels where you have to wait a lot, like Native Fortress. I spent one hour trying that, and got gold with 25 sec spare on the first run I finished.
I still have 8 time trials left, being Slippery Climb and the bonus level in the dark the hardest ones left.