This is an obvious route, but I haven't seen anyone use this, so I figured I'd post it. Saves about 15s.
One thing to mention about the video is that you cannot pick up the replay on foot. My original line of thinking was doing it on foot while doing Trial By Fire, but I only tested being on foot AFTER uploading the video (I know, I'm an idiot), so I reckon that getting a replay isn't worth it. Nonetheless, you can still make it if you don't hit into anything. I guess this could be a route that you use if you hate your run and want to go yolo TriHard
Tested another route and it sounds more feasible: Normal route (get as many magazines as possible)->Cliff by St. Marks Bistro->Gap between fence and building (nearest to the shore)->first left->kill thief (hitboxes of buildings/trailers here are fairly large). This saves around 5-7s and is much more lenient than the route above (~8). If you notice that you're lower than ~18 on the timer before heading off the cliff, then I would advice to take the "normal" shortcut, because going between the building and fence can easily lose time.
Oh yeah I tested that one myself on stream the other day. Not exactly groundbreaking so there was no fuss about it. I like the one on the video more, didn't think you could just do that.
Snipe from Saint Mark's, about 30-35 seconds faster than Megajump strat from comparison above.
A better reference must exist but this is the first I found that worked