Sarge,
Most of the VSF elements included in the game are simply a reduction of relative tech levels or minor alterations to existing rules. The longest dedicated section for VSF (and historically-based forces) deals with infantry formations and their movement; these sections are easily skipped over. Most of the other VSF unit-specific rules (airships, landships, dirigibles, etc.) have been relegated to the optional rules section.
The Depletion numbers are used to reflect the relative number of missiles of each type carried by a vehicle and are (in most cases) no longer limited to firing one missile per activation; each vehicle can fire additional missiles during the same turn by increasing the weapon's Depletion number.
Players can also purchase in-game dice re-rolls as part of their force for any scenario; these can be used to re-roll any single die rolled, including Depletion rolls.
Any other questions, feel free to ask.