When you need to move a long distance you can always pack motorised infantary up into a truck, remember though if you do this that packing and unpacking means that you cannot attack on that go.
Outnumbered
A good strategy when you find your forces heavily outnumbered by the enemy is to keep them close together and find cover.
Various Game Hints
When outnumbered, find cover and keep your forces close together.
You can pack motorised infantry up into a truck for moving longer distances, but packing and unpacking means you can't attack on that go.