Mountains and scenery

YouTube is your best friend.  Look up wargame terrain how to, the scale will be a bit off but principal is the same.  Try the terrain tutor and the plunder den for starters.  They both have a lot of videos and some good basics to get you started.  Also the same but model railroad. 

Model railroader background here. You can make convincing hills from chunks of styrofoam, laid over with shop towels soaked in a 50/50 mix of white glue and water. You can make a lattice of cardboard and do the same thing. For flat areas, I've used cafeteria trays turned upside down, as well as odd chunks of wood, cigar boxes, and milk crates. Of course, if you don't care about backgrounds much, a simple black cloth will focus attention on the track, because the black means "nothing there to look at."

Scenery is easy, and when you get the hang of it, you won't want to stop...lol

I'd use 2" pink foam cut to the silhouette for your mts, 

use a scroll/band saw.  when you get that shape, tack a bunch of posterboard paper to the wall

draw your shape on it (so you can keep track of where the cutouts go)

remove a few at a time, rough them up, and round the edges, then use a paring knife and pop random chinks and chunks.  lay it flat, and paint.

1st coat:  50/50 paint and elmers school glue, allow to dry.  
2nd coat the same, and try to get it on thick this time, dry well
3rd coat Titebond wood glue/paint and thin with school glue if it won't paint,

while the 3rd coat is wet, sprinkle your coating on, liberally, but not thick/piled
completely coat the surface,
spritz it with water/alcohol 10%, and a drop or two of dish soap 


About Texture Coatings:  dried sifted real dirt makes the best looking dirt,
I also use the colored hobby sands, and mix them together for diffent tones

to sift dirt, use a cheap strainer first to get the rocks out,
heat/bake the sifted dirt it until it stops smoking
(I use an old frying pan on the grill)
then sift it thru a frypan spatter screen (very fine screen on these)
save both, as you will have "road gravel" and dirt.
mix the dirt with a couple colored sands (green, yellow, brown, red) gives it other tones
that simulates bare dirt to grassy wild flowers.

pro tips 
Don't over spritz, or under dry.  the coats 1 & 2 Will get soft, thats the point, getting the glue to come from under should create a thick, concrete of base scenic color and texture. 
Working all the panels one at a time makes it easier to have 3-4 in various stages of drying

to add ground road gravel (from above), foam bushes, scrub, or secure loose texture, a water wood glue mix in an eyedropper, or my favorite, a sirachi bottle 
place the stuff drip some glue mix on

also, if you can find an old blender, sticks dried weeds and leaves make a nice 2nd ground cover
(I don't like to spend $$$ on that stuff God gives me for free, and it looks better, too)

mt done?  OK, now pull the poster boards 2 at a time, and paint(or print) the continuous backdrop sky

that was how I built the quarry

www.youtube.com/watch?v=H51GLMTpiL0

any questions, just ask away!

dr

My track is obviously not a drag strip but I did want to have some type of scenes or scenery.  I used and old tarp. Draped it over the bones and support structure.  Painted it to the fit. Used interior wall paint and acrylic paint. I did paint directly on wall as well. Cheap option, but affective. 

Really depends how much detail and fun you want to have with it. Sounds like some of these other folks have some great tips for achieving any look. 

Can't wait see what you come up with. I'm willing to answer a question if you think I can help. 

latest addition the the Goat Hill complex

dr

www.youtube.com/watch?v=rUyL_CeIDtE