for consistency I think you need the linework in the mountains. that way the style matches that of the forest and other areas. I think the black inks are a bit too strong though, so I took the liberty of color-holding the blacks and making them a kind of burnt sienna or raw umber color to de-emphasize them.
I think outlining stuff in brown might be the happy medium between outline and no outline. That being said, it is your map and what you say will be the decision.