The little lass next door solved it for herself - she made friends with me, and now we do lots of things together. I, and another neighbour and friend, expand her horizons a lot. She just uses our given names, but we fill in for her grandparents I'm sure. One set are only a 4 hour drive away, at a coastal resort, but she only sees them every couple of months.
A grandparent of my acquaintance, Roly Sussex (a broadcaster, linguist and my former lecturer) always buys his far away little grandchildren two copies of every children's' book he chooses. He keeps one himself and reads to them on skype, while they hold their own copy.
It would have been nice if skype and PCs were around when my kids were little.