Getaways with solo

Aspen, Colorado

A century-old guest ranch on the Frying Pan River about an hour from Aspen, with cabins, hot tub, sauna and room for up to 70 guests.

Aljezur

A treehouse built into a 100-year-old walnut tree above a mountain stream outside Aljezur, Portugal, with a mini kitchen and eco-toilet downstairs.

Sedona, Arizona

A stylish treehouse stay near Sedona's trailheads, built for couples or solo travelers who want mountain views without the crowds.