The Archipelago Ring Road (Saariston rengastie) south-west of Turku is about 250 km, links a chain of islands by bridge and ferry, and is one of the few routes in Finland where the driving itself is the point.
The ferries. Most of the connections are free road ferries run by the state, and they take a motorhome without any fuss. A couple of the smaller connections in the middle section are seasonal and charge, and those are the ones to check before you set out — the season typically runs from late May to late August. Ferries go on a timetable, not on demand, so the route rewards a relaxed pace.
How long to take. You can drive it in a long day. It is much better over three, stopping at Nagu, Korpo and Houtskär, which have harbours, small restaurants and space to sit still. Out of season several of those close, and the route becomes quieter and rather beautiful.
Camper practicalities. Roads are narrow but well surfaced, and 7-metre motorhomes do the route routinely. Harbour car parks are the natural place to stop, and several have services. Book a campsite pitch in July — this is a popular route in high summer and the islands are small.
When to go. Late May and early June, or the last two weeks of August. The ferries are running, the restaurants are open, and you are not queueing behind everyone else's holiday.
From Helsinki it is about two hours to Turku, so the ring road works well as a long weekend rather than a full holiday.