Basically non PVP people just don't want to get attacked and lose their territory. But i don't think they would mind if they would get involved as traders in the PVP world. With the system i described they would always be represented in the PVP map trough his exit point in the map. The player chooses if he wants to expand and get involved in the fight for influence and land , or just stay back and enjoy politics and trade. And why not mix both , you could have someone give you military support ,trough good politics and trade agreements, and still be able to expand as a merchant.