Grass cut after the double ramps
In the narrow section right after two ramps, trick off the first ramp, drift off the second, then mushroom through the grass and release an orange mini turbo before the grass ends (holding the drift too long cancels it).
Rail-to-palm-tree platform cut
Right after the S-turn, take the green railing, left trick at the very end, trick off the palm tree and land on the platform to cut the grass patch. Big time save, and it can also be improvised from the main road via a wall ride onto the left roof.
S-turn feather roof skip
Skip the entire S-turn section with one feather: go wide, charge jump onto the window wall, trick off the lamppost, hold left and feather onto the roof, then trick back to the road. A later editor's note says an easier version exists - do the normal no-item S-turn sequence, then feather when hopping the second grass patch and land on the same roof.