We live on the west coast but all our family is back east. We've always kept our kids on west coast time when we go back to visit family just so we don't have to adjust their sleep times. It actually works out well for us because we can let family watch them while we go out for dinner and still can be back in time to put them to sleep. Though we miss out on beautiful mornings like today (we're back east visiting family now) because they don't get up til 11am.
It only works going west to east of course. But we had a friend who visited us from the east coast and kept their baby on east coast time. They all went to bed at 4pm and woke up at 4am every day.