What are the precise effects of terrain on unit movement? How many movement points does it cost to enter a hex of each type of terrain, and are there any modifiers to that cost based on the terrain of the starting hex (e.g. Road)?
If your unit has 1 move point, it is not important is this terrain forrest, desert or any other type, it could move just once, except road (1 additional mp for such units, if both movements are over road).
Forrest, swamp and desert could delay "fast" land units (2 mp for each such hex).
Amphibian could move over desert and swamp as over open terrain.
Helicopter has not any bonus (+ or -) for any terrain.