This picture is what I was trying to recreate in my CD3 maps.

After following Gandwarf's fantastic CD3 tutorials, I found that certain design elements (while great) didn't fit my particular style. The term 'organic' is often used when people talk about their mapping style and this definitely fits with what I'm going for. The generic roads built into CD3 might work well from a design point, they just aren't artistic enough to capture the feel that I was going for in my map. So I created a new road tool and style sheet to accomplish what I was looking for.

I'm posting the details here because I'd like feedback from some of the more experienced cartographers. I'm a complete novice at this stuff and the help that I've gotten in just a few short days by reading this site has been incredible so I thought I'd try for two birds with one stone, so to say.

#1 - Give something back
#2 - Get constructive feedback

So here's how I accomplished my Wagon Trail...

Create a new tool.

Start with...
All City Drawing Tools -> Advanced -> City Wall 10'

Click [New]
Rename it. I used "Wagon Trail"
Draw Method - Path Polygon
Click [Options]
Change to 'smooth'

Click [Outline]
Make sure 'extra entity' is selected and hit [Properties]
Color doesn't matter because we're going to be using a fill.
Width - Fixed, 4.0
Layer - Roads
Sheet - Wagon Trails
Fill Style - CD3A_Grass 1*
*use the same fill as your map's main land background. I use '...Grass 1'

Click [Ok],[Ok]

Now Click [Properties]
Click the color swatch and set your "use color" to #157
Play around with your colors and find one that works well for you. On my monitor, color #157 works well when combined with the sheet effects I've chosen (see below).
Width - Fixed, 10.0
Layer - Roads
Sheet - Wagon Trails
Fill Style - Solid

Click [Ok], [Save]

Your tool is ready to go and you can begin using it now to get a glimpse of what it looks like without effects.

Sheet Effects
Use [Move up] to position "Wagon Trails" above "Roads" in the list. We want the Wagon trails to be drawn and rendered before Roads. The reason I've chosen this order is that roads are more heavily traveled than wagon trails and should beat down vegetation remaining from the wagon trail.

[Add]
Glow
Outside
Color 136,136,56 or select color #12
Strength - 0
Blur - 10.0

[Add]
Glow
Inside
Color 203,167,138 or Color #43
Strength - 2
Blur - 2

[Add]
Transparency - 80%

[Add]
Blur - .5

Turn on sheet effects and check out your new Wagon Trails tool and effects.

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Now as I stated above, I'm new to all of this so if anyone has feedback positive or negative, I would love to hear it.

Thank you all.