When you guys use terraforming in/around your rides, do you do it before or after finishing the coaster? Also, do you move use the mountain and hill elevation changer or adjust the height of blocks and then smooth them out?

Which game are you referring to?

Roller Coaster Tycoon 3. Sorry for not specifying.

It depends on the type of coaster I'm going for, if it's something like a mine train I usually do it as I lay the track whereas if it's a hyper coaster I'll do it afterwards. If I want a very specific look to the terrain I'll go in and do it tile-by-tile, but most of the time the larger brush tools work fairly well, just remember the smooth tool is your best friend.