Absentee owners..accessing property?

[Matthew J. T.]

Let's say a person lives out of state, and you are looking to purchase there vacant property, you negotiate it, do all that stuff....But how do you actually get access to inside the property, if the seller lives a distance a way from the house? What if my end buyer wants to look inside, but can't because there is no keys access? I'm a little confused how that part of it works...