The Trail Blazing activity, more than any scrape or scratch in this otherwise glistening gem, makes me want to hurl my disc out the window. For reasons unbeknost to me, that activity infuriates me more than any bullshit I think I've ever seen in a video game. I drive the Toad and I try to get to the targets, and sometimes I get awarded with a handful of seconds, sometimes I get quite a few, but one thing I never get is to the end. Am I missing something? Is there some high level strategy that I'm unaware of? What am I even supposed to be doing?

Trail-Blazing is one of my favourites across the entire franchise. It's also one of the easiest; seriously, just keep following the checkpoints while smashing through as many cars/people as possible (the more people/cars you hit, the more time you're awarded when you hit a checkpoint). It's hard to give much of a strategy to success because of its overt simplicity.

The Trail Blazing activity, more than any scrape or scratch in this otherwise glistening gem, makes me want to hurl my disc out the window. For reasons unbeknost to me, that activity infuriates me more than any bullshit I think I've ever seen in a video game. I drive the Toad and I try to get to the targets, and sometimes I get awarded with a handful of seconds, sometimes I get quite a few, but one thing I never get is to the end. Am I missing something? Is there some high level strategy that I'm unaware of? What am I even supposed to be doing?

If you're running out of time, you're not hitting enough pedestrians and vehicles. The point is to cause as much havoc while getting to checkpoints. It's fun! Side note: I felt this way about insurance fraud, until I discovered the beauty of getting my ass run over on the highways

Running into things also seems to give you a speed boost in addition to banked seconds. Not only cars and people, but also lampposts and newspaper bins and all that. The only thing that makes it at all difficult is getting past your gaming reflexes to dodge out of the way of traffic.

Trailblazing is a joke (whether it be for better or worse) once you just ride on the sidewalks.
 
The streets aren't as heavily populated with cars as you'd want them to be but there are always tons of peds and they get you tons of seconds
 
Just ride down the sidewalk instead of the street while dodging the occasional telephone pole. 
 
Easy Peezy. You'll have more seconds than you'll know what to do with.

I hate Trail Blazing as well, and i had to aim like an damn idiot to hit people to get more seconds (since vehicles are only worth 1 sec). Cyber Blazing is 1000 times better.

Trailblazing in co-op is even easier. You can mow through cars and your friend can toss molotovs at pedestrians.

Others have nailed the basics, only thing to add would be that you don't have to follow the road on all of them. Keep an eye on the radar for where the next checkpoint is; I found multiple points where I could cut corners giving me plenty of time to make it to the end.