One of my maps...

[Robbie]

This is a very rough sample...I exaggerated the road and the effect so you can see it clearly. You may want to make it a little more subtle.

I created a quick and easy land texture (brownish) and then I created a new layer on top of it set to color burn as its blend mode.

I made my draw color f4be9e which is a light tan. copied that html color code to my clipboard because I'll need it again.

Then I drew a road line with a size 9 brush on the empty color burn layer.

As you can tell because its burnign the tan onto the brown you end up with a mix of the two...it keeps the texture underneath it.

Then I applied an outer glow effect to the road layer. I set its blend mode to color burn. Opacity to 100%. Noise to 9%. color to f4be9e (same as the road) Spread to 0, and finally size to 18.

You may have to adjust things as necessary to achieve the look you desire...but color burn is an awesome way to blend things into a textured background. If you have a darker background and want a lighter colored road, do the exact same except use color dodge instead of burn as your blend mode...you may have to experiment with colors to see how each color dodges into the darker background.

For the two rivers I used colro dodge on both layers...the river and the top rivers glow was both done in color dodge with 1c21ff...whereas the bottom river was color dodge with 1c21ff, but I used color dodge with 727d4a for the outer glow to give it a beach-like edge...

Again exaggerated, but you get the point.