I did Iceland last fall, solo, as a 6 day whirlwind tour around the loop road (yes, it was awesome). This fall (late Oct) I'm getting 4 days with the wife and am looking for the coolest excursions around the Golden Circle, which I mostly skipped last year. We'll be staying south of the GC in Selfoss with a small 4WD vehicle, but don't intend to go offroad.

Both of us are semi-fit (lol-American) so casual hiking is great, but probably should keep it to 10 km / 500-600m rise for a single hike, and under 15-18km a day total. Free is nice, but for something really cool we could spring $150-200pp for a tour.

Oh, and I'd like to find a hot spring that is not as pricey or as busy as Blue Lagoon; ideally quiet and casual.