Maybe I am missing something, but why would people need to hike 10 hours to La Sirena from Los Patos and carry water etc (thank goodness I finally found a map) when it appears that La SIrena is located right next to the shore. So it seems that its easy to just take a boat transfer to it. At least from La Leona's side it appears to be a short distance? It seems that one can take a boat transfer with all the necessities--even food by boat and then stay roughing it at La SIrena, taking 2 hour hikes in the morning and evening. ???? There is also a private charter option at $350 max capacity 5 people but I am leaving this aside for now as it looks a bit complicated & expensive. Many thanks.