Machu Picchu

Alright, so I've been trying to plan my Machu Picchu trip for some time. Considering I have to arrange a flight from Lima to Cusco, then a train from Cusco to Aguas Calientes, and then a bus from A.G. to Machu Picchu, I'm a little concerned about a glitch popping up somewhere in these travels (if their time-keeping is anything like in Spain).

Here is what I'm planning on right now:
June 15, Monday- fly to Cusco early morning.
June 16, Tuesday- take the 7:42am train to Aguas Calientes (the only one I can afford).

Here is what I'm unsure of...

Either stay in Aguas Calientes for the night, go to M.P. at like 6am in the morning to catch the sunrise, then spend the day there and catch the afternoon train back to Cusco, OR just spend the whole day of the 16th at M.P. and come back that same day. I won't get into Aguas Calientes till noon on the 16th, so I'd like to get there early to avoid crowds and hike up Wayna Picchu (http://en.wikipedia.org/wiki/Huayna_Picchu).

Here are the hostels I'm thinking of:
Aguas Calientes: http://www.wiracochainn.com/location.html ~$55/night
Cusco: http://www.sanblashostal.com/ingles.htm ~$25/night

Either way, I'll probably spend the whole day in Cusco after I do M.P., then head back to Lima early morning on Thursday or Friday.

Suggestions (especially from experienced travelers) accepted :)