I second this guy's opinion. It's likely terrible latex house paint, and will have marginal adhesion to the underlying finish.
I would add that a hot water kerosene pressure washer would be the right choice here - it will blast a paint with marginal adhesion, and possibly the stickers, right off the bus. You will find where all the rust is hidden. Once you've washed it for a while, see what's left and use a smart eraser wheel on the remaining stickers.
Let everything dry. A flat 4.5" twisted knot wire wheel on an angle grinder will strip paint quickly, but I would only do that after you've tried the steam pressure washer.
After all that, you'll want to scuff all the original yellow paint, fix the rusty parts, and then apply an epoxy primer.
Originally Posted by Goatherder
If you have latex house paint on there...you might consider renting a commercial-grade pressure washer. I'm talking one of the 4000 psi models used for cleaning masonry and the like. You might be able to blow most of the house paint right off the metal surface with that, and greatly reduce your workload in one easy step.
Just be careful with it; don't hit your leg or use it on the grille in front of the radiator. I once knew a brick mason who decided to pressure wash the bugs off his grille...and all this green juice ran out on the ground...
Then remove the stickers with a Smart Eraser Wheel.