Hi, and thanks for reading! I think Snæfellsnes is a good choice. You’re (just) past the period when weather will be an issue, or at least it shouldn’t be a major one.
The choices that come to mind for me are Snæfellsnes, the South Coast, or the Reykjanes Geopark.
But those won’t save you much driving if any. And Snæfellsnes has lots to see once you get there, without too much driving in between stops. So I think your instincts are great!