Skip the peak since volcanic activity restricts summit access, but trekking the Valle de las Tumbas makes you feel like you landed on another planet. Prepare for thin, freezing air at 4,000m+ and bring serious gear. The 'Snowy Ruiz + Hot Springs' tour is worth the $150 to handle complex permits and transit from Manizales. Spend four hours navigating barren, ash-covered slopes before you soak your sore legs in the nearby hot springs. Don't cheap out on transport.
