Well... the problem is space... and how to deal with that problem
First, check your supply of bricks.. that give's you an idea of what you can or can't ..
By building a multi level train section ( mountains ) you can place more into your layout quite simple, but, as you said, the problem is you don't have the bricks .. well you can fix that by sloping your plates . Make something a base , fix a hinge stone to it, build it to the proper height, there you go, one easely built embankment. ( for the straight parts anyway.
you can stuff any kind of color into it, nobody notice's it ... you can make this into bricks after a while, if you got the bricks.
Personaly, it's maddness just to try this all just for a home made lay-out, make fun, chance it, play around with idea's and see how far you can go ... don't stare yourself blind on everything you see.. your imagination is more important than a neatly made lay-out you don't want to mess with because it's so pretty ;-)
All great builders started somewhere ... this is your starting point.. now reach for the stars !
Greetings, Saint