Who this suits
Visitors who want depth, not just coverage
Averages 80–190 km of driving daily — genuinely relaxed, with high weather slack and room for a guided activity (glacier hike, boat tour) without derailing the rest of the trip.
Where the extra days go
Snæfellsnes, plus real rest
Budget a full day for the Snæfellsnes loop (Kirkjufell, Snæfellsjökull, Arnarstapi) rather than a drive-by, and use a second spare day wherever weather or interest points — Mývatn's full circuit, or an extra night in the Southeast.
Fourteen days still isn't "no planning needed"
Even with slack, book South Coast and Jökulsárlón-area lodging early — availability, not time, is the real constraint on this stretch in peak summer.