You cannot buy Eurapass in Europe, except some country passes and not as attractively priced as the Eurail Passes.
For a family of 4, if not going by tour group, would be better to either drive (despite the high price gas) or use LCC (Low cost carriers) to fly between big cities.
For a family of 4, if not going by tour group, would be better to either drive (despite the high price gas) or use LCC (Low cost carriers) to fly between big cities.