What you want to do is this:
Import the dwg into a revit drawing.
Explode it. You have to do a full explode, any unbroken blocks will not be editable.
You will need to select the lines by the layers, and then assign them to revit line styles. You can select all and then filter, the layers will show and you can grab them layer by layer and re-map them to revit linestyles (thin, medium, wide, hidden, etc) as appropriate. You might need to create a few revit linestyles depending on your tastes in drafting.
Do the same for Text, and Dimensions.
When its all done, select all and then copy/past the whole mess into a new blank revit file. You need to do that because exploded autocad files leaves dozens and dozens of line types and text styles and all kinds of garbage that you need to get rid of, and it will be left behind in the first file. Then save the 2nd file, and thow the first one away or keep it if you need to backtrack and re-do something maybe.
After that you can decide what to do with all the revit line work.
You might consider using the dwg as a linked underlay, and adding revit lines and objects over it as needed and doing some basic edit work in acad to the dwg if needed. That's what we do. You can override all the colors, weights or lines styles of the dwg as you like in the view and it will look fine, and you can turn off what you don't need, after you have drafted over it. If the contours are at 3d elevations, you can create a toposurface from them, which is really what revit wants. Even thought the revit site tools are very, very weak.
Have fun!
