Can anyone recommend easy (via boat, bus, or train) day trips from Piran to elsewhere in Slovenia or neighboring Croatia? I'm thinking of spending a night or two in Piran or, perhaps, more if there are good day trips to be had from Piran as a home base. The loose idea is to ferry to Piran from Venice (via Kompas' Prince of Venice cruises) and then bus-train back to Venice via Trieste or ferry back the way we came. Ferries only run once a week in April, so that's why I'm researching day trips; trying to figure out if we should stay for a week in Piran and explore from there or just stay a couple nights and then bus-train it back to Venice.
For example, how easy would it be to bus from Piran for the day to Rovinj? I'm very interested in seeing nearby towns that were also part of the former Venetian Republic. Any towns you can recommend that are easy to get to via Piran by boat or bus (or train?) would be great.
Thanks in advance for your help!