2015 frame rust starting to develop

June 2015 here. It appears you have more rust than I do with a tad less mileage but it's hard to say without any good images. With the images you did post, looks like a drag mark from crossing or tethering.

Don't get me wrong I definitely have rust spots but for the most part it's really clean.

BUT...I keep mine mostly garaged and I have the luxury of washing salt/brine off in the winter though too (indoors).

This year will be my first time doing some PM on it (have had it since Nov 2016).

 

Oil is not the answer . 3 coats EPOXY PRIMER followed by 3 coats any frame paint such as Eastwood xtreme chassis black , all done afterna major prep job of course . I have a 2015 trd pro which has never seen salt and never will ,sits in carpeted garage for moisture barrier all year when not driven but parked all winter in Nj . Salt or brine wins that fight always so don't let it . Buy cheap car with liability only for winter , peace of mind and save your Tacoma or any valuable vehicle . Salt on any frame for even 10 minutes starts its damage so washing it on weekends in winter helps but no way will that stop it ! Park it in winter and be smarter than SALT !

 

What is "winter"? Sounds like it sucks...

 

What you need to be concerned about is the parts of your frame that are sandwiched together. Those areas are where you need to fluid film or whatever. Get it in all the cracks and crevices. The factory applied coating doesent stick to the welded areas very well,it's a very uneven surface. But those are easy fixes.

 

In the words of neil young rust never sleeps