I don't have access to the rules set but I will venture some comments on the terrain
Unless the rules have some way of abstracting it the terrain looks too open. http://www.dtic.mil/dtic/tr/fulltext/u2/b004383.pdf has some interesting graphs on maximum spotting ranges and maximum shoot in ranges. Theoretically max LOS from any given defensive position is 300m or less (ie two of your hexes) 63% of the time. However that doesn't translate into shooting distances. 66% of engagements take place at 100m or less and 85% less than 300m. Of course it may be that the rules limit shooting to 2 hexes so take this into account?
I assume you are familiar with Army Operational Research Group report 17/52, An Analysis of Infantry Advance Rates in Battle (WO291/1159)? If not there is some info in:http://www.testofbattle.com/upload/bob/Benchmarks.htm That piece of reserch would apper to be very relevant t your game.
Yahoo Forum: Simulating War
A "Hill" hex contains Hills (naturally) of several heights, Woods, Open and even a Building plus there would even be paths linking terrain features together (see below):
A "Woods" hex has yes "Woods" but also a road/trail through the woods, a feature slope leading up rather than a hill per se, another inking of a building and clear (see below):
Ultimately the terrain cost would be different and cover benefit would be different depending on the "side" you entered from.
US Colonel David Schroeder presented at Connections UK 2014 an interesting keynote address where he explained part of his WWI game design which took the Hexagon and broke it down into six triangles, each with their own terrain type. So the cost to enter and combat terrain benefits depended on which direction you came in from (see slide 57).
Food for thought! I am thinking that the core Hex should have a terrain type (the predominant terrain type) but each Hex has its LOS and movement cost.