Hi thundering1 - a suggestion for you...

Now you have your very own height-map, and if your version of Vue supports it (I have V5I and no earlier versions) try the following....
Use the height-map as a guide for where to draw your roads in your 2D app (on a separate layer). The roads should be all the same grey-scale value (pure black or pure white are probably easiest).
Delete/clear the original height-map and save just the road-map (pun intended)..

In Vue, load your height-map into the terrain as usual and do your tinkering. SAVE YOUR SCENE! The next step cannot be undone! You only get one chance at it per go...
Go back to the terrain editor, re-enter the "picture loading" dialogue and load the roads into the 2nd slot.
The roads will now be combined with the terrain. Any part of the roads pic that is not black will uniformly raise the terrain it's sitting on (it is ADDED to the 1st pic).
The amount of influence can be controlled...If your roads are white on a black background, then the roads will be raised. If "negative" (black on a white background), then everything except the roads will be raised, giving the effect of sunken roads. Be warned that you have to use fairly large maps to avoid pixellation...1024x1024 might not be enough. Also be warned (again) that once you leave the picture dialogue, Vue will immediately consolidate the 2 pics into a single one.I have yet to find an easy way around this problem - it means you've got to get it right in the pic. dialogue...

You can then use the same road-map to control the texture strengths, thus enabling you to apply a different texture to the roads...(which might be all you need to do in the 1st place, you might get away with not having to alter the terrain)...

You can use the same technique to carve out river-paths, except for those you need to create river-maps that have blurred edges and vary in width... Getting a texture onto the rivers is not an easy task tho. I've tried a couple of approaches, but nothing too successful so far. Working on it...

I think I've got that right.
If not, at least it'll give both of us something to play around with for the next few days:-))

Cheers,
Diolma