We decided to walk from Copacabana to Yampupata, which is just across the strait from Isla del Sol. The walk was beautiful, and a fairly easy 4 hours (tho the sun is seriously strong here!): we had stunning lake views most of the time. We also passed local highland people releasing their llamas and donkeys to graze after work - highland Bolivia as you imagine it!
Isla del Sol is incredible - the Incas really knew how to pick their sacred sites! Wonderful views of very blue Lake Titicaca, Coati (Isla de la Luna), and the snow-capped Cordillera Real. We watched the sun set and rise (which seemed appropriate since it was born here!), visited the inca ruins, walked the 'spine' of the island, sat on one of Bolivia's very few beaches, made new friends, and generally loved it here!