So this is the basic outline of what I've been trying and a few cards I've run.
Its sorta based on the game mechanics of "Arkham Horror", where each card has 3 or so different events and by mixing them around you get a pretty random selection.
I haven't tried more "scenario" type things like sniper attack or trap or giant trantula or the like but I think that'd be a great idea.
nat
The Brain
Each card gives a unit a short term goal.
Once that goal is completed they get another card.
If a given unit takes more than 25% casualties they draw a new card.
Once a unit reaches an objective the unit holds until a card tells them to move on.
Sometimes you have to sorta cheat it to make it work.
Some cards have special orders for heavy weapons.
Advancing: this is moving towards an objective but before this unit has fired or been fired upon
Engaged: This is still moving towards an objective but once this unit has fired or been fired upon
Holding: This is once a unit has reached an objective.
Objectives are usually determined by the scenario. An example of an objective is "the temple" or perhaps "the gate"
or "the ford in the river".
Advancing: Flank right from soft cover to soft cover until engaged.
Engaged: Attack nearest enemy unit.
Holding: Stay here firing at most powerful enemy unit, or heavy weapon if within range.
Heavy Weapon: Fire at enemy's hero/leader unit if possible, if not fire upon largest unit.
Advancing: Flank left to first hard cover.
Engaged: Attack smallest enemy unit within range.
Holding: Move on to next objective.
Advancing: head down the middle from soft cover to soft cover until engaged
Engaged: advance to charging range and then charge nearest enemy unit whatever the size.
Holding: Move to hard cover that has oversight of the objective and fire on any enemy units approaching
Advancing: Flank right until engaged.
Engaged: retreat to nearest hard cover.
Holding: advance to next objective (if no more objectives fire at weakest unit within range)
Heavy Weapon: move to nearest hard cover within range of objective and engage enemies holding it.
Advancing: advance through soft cover until you engage, exchange fire for one turn, then retreat out of range and flank around enemy unit.
Engaged: fire one more turn then retreat out of range then flank left.
Holding: advance to next objective but draw new card at next hard cover
Heavy Weapons: advance without engaging enemy as fast as possilbe to highest ground within range of enemy.