During the movement hazard phase, creatures may only be played in the order of the regions moved through/site path on the site card. For example, a company is moving through Lorien, Anduin Vales, Grey Mountain Narrows, and Withered Heath to Gold Hill.
The first region is a Wilderness, so creatures keyable to a single Wilderness may be played. Once that is done, the next region is a Border-land, so only creatures keyable there may be played, and so forth. Only when they reach the Withered Heath do they have a Double Wilderness, and so only then can Double Wilderness creatures be played, though creatures keyable to a single Wilderness could also be played at this point. Finally, creatures keyable to the site may be played.
Just to shake up the hazard strategies a little bit.
For added fun, any hazards that affect/have a condition for a given region must be played when the company is "at" that region during their movement, and hazards that affect/have a condition for the site must be played last of all.