It sounds like that the problem is that your attack are not interesting enough, they expected the attacks, if you do not attack them, then it's more than not interesting. It is disappointing instead.
But, did you tried to attack them with muse and unexpected.
idea:
- the prince have lost his gold bag which is planned to reward the players.
- oh, for some reasons, destination change.
- The princess want something special in the mid of journey and refuse to co-operate.
- The encounter a circus, and they are mused and stay for a few days, then they found they used up their rations.