Thanks for all of the information.

Is it better to spend 1/2 a day in Ollanta in order to spend the night in Aguas Calientes and see more of MP, or should I spend a full day in Ollanta and take the early train to MP? Is there anything else to do in Aguas Calientes aside from the hot springs?

Also, would anyone recommend spending 2 days in Lima and 3 days in Cusco, or 3 days in Lima and 2 days in Cusco? I've heard that Cusco is more interesting than Lima...

Finally, what's the best thing to do with luggage at MP? If I'm visiting MP in-between hotels (Ollanta and Cusco), is there a secure place to store my luggage while at MP?