Villarrica National Park
Many people pay 50 euros+ to be led up to the summit of Villarrica. It's only accessible with a guide, which is offputting... It didn't sound like my kind of thing: instead I did the Villarrica Traverse walk, which traverses the National Park (going round the lower slopes of the volcano). There weren't many people... In 4 days I saw a couple of hikers, a few tents, and a few day hikers, horse-riders, cyclists etc. near the central lower section where there's easier road access.
There are some amazing landscapes - volcanic scoria everywhere.