Well, this has been on my to do list for quite while now. I have done it once, 11 years ago when we got married and we spend a few days off on our honeymoon on the road and in Houtskär island. I have always wanted to go back, since the scenery is beautiful and I have tried to make it last summer, but I didn't get to do it.
So, this year I am prepared a bit more. I have checked the schedule of the ferry between Iniö and Houtskär, which only is in operation from mid-May to end of summer, early September.
You can find the crucial time table from here. I spend more than you should have to find that on that website, it should have been much easier to find.