As we'll be arriving to Iceland around mid April, it'll still be cold (max. temperature would be 7 degrees and min. temperature would be apx. 0 degrees).
That means, we cannot access the middle part of the island (plus - we have no time for that), so we'll have a nice 10-day stay - enjoy a day or two in Reykjavik, rent a good 4x4 car and tour the island on road number 1 (the only major roan in the country).