I'd say the same. But perhaps change your plans slightly so you stay in one place and not have the hassle of organising and the exhaustion, of moving around. Find a nice little Hôtel or appartment- and spend some time just relaxing and reading, swimming and local sight seeing and walking. You won't get the money back on the flights anyhow- and if the worst comes to the worst, you'll just have to pay to change return for earlier date. Go and have a good rest- enjoy.
There is an admin cost for chaing dates, + the difference in flight price if there is one- but at that time of year it won't be much- and hopefully you won't have to.