The Onepass rules allow one stopover (I assume that means 1 per round trip). The CO site also states that "Stopover Rewards allow you to take a scheduled break in travel on the route between your point of origin and your destination city."

If I'm in Barcelona, I assume that Lisbon could be a stopover. But what about London or Dublin? Is it worth asking if somewhere in the wrong direction is possible (Prague, Athens, etc.)?

I also plan to be in Strasbourg, so I could plan to be there at the end (and Barcelona at the beginning) and make more locations available "on the route" when I'm returning.

Anyone have experience with trying a not-so-direct route?

Thanks for your insight.