We really enjoyed Isla del Sol for the pure relaxation of it. We got a boat (I think with Chakana Tours, booked through our hostel) to the North of the island. We did notice a guide hanging around trying to corral people getting off the boat - but we understand the guides are an additional cost unless you have expressly booked one. We were advised by friends that the north of the island is quieter than the south and, since that's what we wanted, we went off in search of accommodation. We stayed at 'Mirador del Sol', which is found by walking to the right as you disembark the boat -walk over the rocky bit (there are steps cut into the rocks) and around the bend (only about a five minute walk from the boat). We paid 25bols each for a double room which had a window on both sides looking out on each of the the back to back bays - beautiful. It was basic, but clean with outstanding views. Bathrooms are shared.
The exploration of Challapampa only takes about half an hour total, but its just a nice place to sit and look at the lake/mountains/birds and the stars at night.
We set off on the ridge hike the next morning - from north to south of the island. We loved the hike - there are a few hills where you need to take it easy (really due to altitude), but overall it was not too much of a challenge and the views were beautiful. We didn't do the ruins, so only paid 15 bols each at a bolletaria near Challa community - we didn't encounter anyone at any of the other (what we thought were) bolletarias, perhaps as we walked the trail quite early in the morning (left Challapampa at approx 7.15am). We think the costs are negligible though for a great walk and a way to support the local community directly and think some of the comments on here complaining about the charges are totally ridiculous! Even if it costs 30bols each (10 for ruins, 15 for north, 5 for south) - that's £3, approx. €3.50, $4US - are people really travelling all the way to Bolivia and begrudging paying this small charge for a truly lovely walk/hike that supports the local community that is greatly impacted by we travellers!?
The south of the island definitely had more places to eat (there were only a hand full in the north) and stay - but we preferred the north. We also think the hike from south to north would be much more difficult as you have to do a lot of climbing early on from the Inca steps to the highest point of the island, whereas coming from the south, the climb is gradual and the Inca steps are a descent.
It is easy to pick up tickets for the boat back to Copacabana at the port - boats depart for Cops at 10.30am, 3.30pm and maybe one or two at 4pm.
If you own or manage Isla del Sol, register now for free tools to enhance your listing, attract new reviews, and respond to reviewers.