Questions

[Mr Grumpy]

Just some extra info...........

On point 2) Units would also have to go on foot if attacking into marsh or swamp and to move across an escarpment hexside.

On point 4) As Rick says AT guns are very vulnerable in front line hex's as they need to change into T mode to leave the hex and are often wiped out by def fire, many players feel the loss of points for this outweighs the AT guns defensive abilities and so will have AT guns as blocking units in case of a breakthrough (as Rick said) or to dig IP/trench's or to man a trench/IP/bunker hex to prevent it halving in value when it is unoccupied.
An AT gun with a range of 2 (or more) hex's can be deloyed in a higher elevation hex and then fire "over the heads" of the front line hex's and will also be able to move away without worrying about T mode problems.

Hope that also helps.......:)