I Ace and collect all of the currently accessible single-player Goodies in the "Lowrider" level. (Well, technically I suppose I "missed" one that I could have gotten, but that's in a Cooperative Challenge area and I pick that up when I get the co-op portion done in a subsequent video.)
If you're like me, this might be the first level where you start to feel challenged. When I first played the game, this is where my progress slowed. My skills are more honed now, but collecting all of the Goodies and Acing every level from here on out is going to be more difficult than doing the same for many of the previous levels.
It's worth noting that sometimes the Bacon Slab Sticker Prize Bubble will fall to the left when it's pushed out of its alcove. If you pushed it out and it's disappeared all of a sudden, check the lower areas. Whenever it fell for me, it often came to rest next to the bottommost Piston Lowrider.
I would say that the most difficult part of this level is acquiring all of the Prize Bubbles on the spinning bicycle tire with (and near) electrified hazards. It is easy to die by falling into one of the electrified border hazards or by not clearing a jump over a hazard attached to the spinning bike tire, and you should be wary of that if you are trying to Ace this level.
The last car's Sticker Switch has always been a source of confusion for me, but I think I recently read something that helps to explain it. When you hover a Sticker over the car, you hear the sound indicating the correct Sticker, but the light turns red (instead of the usual green) and seems to disagree. Odd, isn't it? When I first played the game, I remember that red light stumped me and I subsequently couldn't figure out what the "correct" Sticker was. Apparently, this Sticker Switch, insofar as the Sticker Switches that appear in the Story Mode go, is the only one that can be activated by any Sticker. In Create Mode, there is an option to allow Sticker Switches to be activated by any Sticker (instead of a set specific one), but the overwhelming majority of Sticker Switches in the Story Mode of the game require a specific Sticker to activate, so you can see where the confusion might occur when that pattern is broken.
Also, in case you are curious, I'm wearing the Spacesuit DLC Costume in this video. This particular DLC Costume has only appeared for short periods of time in the past (though it was free to download when it did), but it resurfaced in the PlayStation Store starting from the North American release of LittleBIGPlanet 2 (which was January 18th, 2011) and I managed to nab it during that window of opportunity.
Revisit: After getting the Route 77 Sticker (that can be found partway through this "Lowrider" level).
Now that I have the Route 77 Sticker, I quickly revisit the "Lowrider" level to pick up the rewards from that Sticker Switch. Then, I cover the Cooperative Challenge (and its exclusive Goodies) for this level.
As you can probably tell (from that ever-helpful blaring alarm sound), we had a rough time with this one. Fortunately though, as shown in the video, you don't have to make it all the way to the end; You only have to make it far enough.
Special thanks goes to the random online player featured in this video. She goes by the PSN ID of bigdogstompin.