rust is inevitable brah.
don't run it in the winter.
This is the reality. And you shouldnt need a special tool to get oil on everything, Metal is porous and will absorb the oil. If it is already undercoated, don't lube it up. If you really need something to get into nooks and shit my first thought is a dollar store turkey baster or a syringe and some tubing.
Or you could bring it to hecklers "rust proofing" shop and have them preform an anti corrosion voodoo dance, but your money is still better spent on fortune cookies because at least you can eat them.