well there's this: Assuming you want to roll your own, I see a lot of convincing roads done in styrene and in 1MM craft foam. For those google will be our friend.
I don't use Unitrak, but I currently pave all my roads (including street trackage and grade-crossings) with Woodland Scenics "Smooth-it". Instead of using their paver tape, I line the roads with styrene strips and glue them in place. Can't recall what strip size I use right now, but I choose a size where strip height is even or slightly lower than the railheads, depending if I want a slight crown or not. I then trowel in the plaster, smoothing it out with a joint compound knife that can at least straddle from a rail to the nearest adjacent plastic strip. Track flanges will need to be cleared with a tiny tool as the plaster begins to really set up. If still too wet, the plaster will sort of tear as you go. You want it to carve out of the flange with repeated passes until you get the desired depth (ideally, just barely above the track spikes with the track I use). I use one of those tiny hobby screwdrivers for this. I then color the pavement with their asphalt "top coat" paint (if concrete, their concrete colored paint). Straight, undiluted asphalt paint renders fresh, dark pavement, but if you dilute it with some water, you can achieve a lighter and more aged look. It all takes a little practice to master (If you ever really do master it...it sometimes has a mind of it's own, it seems) and I recommend starting in a less prominent area to get your feet wet first. Note- I've tried joint compound in the past, which a lot of people swear by, but I find it tends to shrink and sometimes even crack. I have not seen any shrinking or cracking at all with the Smooth-It.
@tehachapifan's photos look amazing. Only thing I would add is its easier to clear the rails if they end up slightly proud of the pavement, but that's not an easy thing to accomplish.
I like to use 1/32 inch balsa wood for the base covered with fine grit sandpaper for roads. It's easy to cut with a pair of sharp scissors. Joe
Typo, should have written "clean the rails". Hard not to mar the pavement's paint job if they are flush.
Nskale on another board designed a crossing that you can 3D print. He doesn't have a thingiverse account and asked me if I would put the print files up on my account, which I did. You can find more info on the crossing and links to the print files here..... http://1fatgmc.com/RailRoad/3D-Printer-Others/page-101.html I designed some crossings for ME code 55 that might work on other N track to some degree but wouldn't be very ideal for Unitrack I believe. You can find those here ..... http://1fatgmc.com/RailRoad/3D-Printer/3D-Printer-Index.html Sumner
I used wallboard mud for all my paved roads and parking lots. Trowel it in and level it down to the tops of the rails and curbs. Allow to dry until it is not sticky then using a truck with a set of wheels with the largest/deepest flanges, mine was an old Model Power offering, run the truck up and down the track a few times to cut an initial set of flange-ways. Once the mud is completely dry wet it, this will "Melt" the surface layer, then using your fingertip in a circular motion you Zamboni the mud smooth.
