expand_less Ledge Campaigns have more immediate and triggered actions than normal.  I prefer to use a first-in, last-out method, similar to the stack in Magic: the Gathering.  For example, if an action A provokes an attack of opportunity B, then B will resolve before A.  Similarly, if another character declares an immediate action C in response to B, then C will resolve before B and A.
In some cases, immediate or triggered actions can't resolve after the entirety of the action or effect they're responding to.  This is handled on a case-by-case basis.  If the actions of multiple characters would trigger simultaneously, they're placed on the stack in initiative order (or an order of the GM's choosing outside of combat).