I’m using a product called Electric Avenue from Proto 87 to do street-running track:
I really like the way this looks. In the picture, the cobblestone pattern has been fitted, but I’ve only painted and weathered it on the right, so you can see that before-and-after.
The rail comes in short, pre-formed sections with your choice of radius, or straight. It’s rail, not track, so you have to fasten it down and maintain the gauge. The sections are only 3 or 4 inches long, so they are easy to work with, but that also means you have to maintain power. I found that to be a real problem, as solder wanted to flow into the groove and mess up the track. I’ve got some more of this to do, and my plan is to solder a feeder wire to each section on the underside so I don’t have to solder the rail itself.
Earlier, it looked like this:
This shows the cobbles a bit further along, still not perfectly in place and glued yet. It’s where I am right now on the project. For the base here, I used plastic-coated Masonite, sold as shower liner at home stores. Plain Masonite might work better at holding the glue. I outlined the buildings on the cobblestone sheets, and cut out the base, so the building sits beneath the level of the cobbles. This is a nicer look, and it keeps light from leaking out under the wall if you illuminate the structure.
Their web site has more information. They have a lot of different pavement options, or you could just use the right thickness of styrene sheet. This is HO only stuff, I believe. They also have all the parts you need for tu