I think 7538 and 7539 should be tertiary road. I went there last week (2020-07) and it was really horrible. My navigation navigate me there, because 7549 and 7539 have the same priority as 7538. Highway 7538 is much better. But I don't know if it's correct to change this only on my mind. 
I leave it like that for someone more experienced for this territory.