Unfortunately, the OP doesn't include enough information about himself or others in his group. What are they interested in? Culture, history, food, wine, scenery, What are their skills? Languages, ability to deal with foriegners, cycling, athletic ability? There are a lot of places that would be a good base for cyling; perhaps the OP hasn't explored his own area by bicycle.

Before I took long tours, I used my bike to discover my own neighborhood by bike.