shrimpmom

Thinking ahead to planning a Europe river cruise with my son and daughter who are in their early/mid 20-s. I'd expect that we'd be very active with excursions but I also don't want them to be completely bored with activities/amenities once they're back on the ship. Without breaking the bank, what would be the best cruise line to consider? We'd probably be most interested in the Danube but open to other suggestions.