Extra Days On Disney Pass

[LOLA2]

Quick Question - Does anyone know the answer to this. I am going on the 3 night land and 4 day sea package. We get a length of stay pass when at Disney. I heard on another site that they will give 7 days and you can use before or after your stay within 14 days. I can't book any more days at Poly too expensive. Can I stay somewhere else for a couple days before poly and still use the 7 day pass, or do I need to stay there? Would I go there and pick up tickets before I am even staying at Poly? Hopfully someone knows the answer.