H Carrie,
It was my first time to Corfu/Arillas last year. I did lots of internet searches for the day trips months before i went as i like to be organised so that i can relax once i'm there. I only had a week last year, so didn't have a lot of time to fit much in, but i did go on a few.
I did the boat trip across to Erikousa for the day (€21 i think?!), the Horse Trekking in Kassiopi (half day) (€28) and the coach trip to Paleokastritsa for the day (€12) - They were all fabulous!
Rachel x