need a bit of advice again reagarding the stay at aguas calientes .
I have 3 days to divide between cuzco and machupichu.I am taking a train from cuzco to aguas calientes.
Should I spend the night at Aguas calientes and come back the next day evening and just have one day for cuzco ..or should I come back the same day on the train by evening and have 2 days to spend in cuzco..and are the hostel/hotels inexpensive at aguas calientes.
I would go back to Cuzco. I had 5 days in and around Cuzco which was just about enough.
Take the first train in the morning and the last train back and you will have plenty of time at Machu Picchu.
I liked Aguas Calientes and I usually suggest spending at least one night. But when you only have 2 days in Cusco, don't even consider it. 2 days is just not enough.
so machu pichu just for a day and cuzco for 2 it would be!
I just spent a day (07:00 through 16:00) in Machu Picchu (coming in fresh from the classic Inca Trail), and I'd say that a single day is definitely on the short side for this city, especially if you want to see the further-out parts like the Sun Gate, Inka Bridge and especially Wayna Picchu (which is a very exhausting climb, but gets you some of the most awesome views imaginable (go stand in line no later than 09:30, as they only allow 400 people a day up, and they're very strict about it)).
So yeah, I'd recommend two days for Machu Picchu. I wish I'd had that much time. Of course it matters how interested you are in the site, and maybe a single day would be enough if you know you're not fit enough to do Wayna Picchu.
Cuzco is a really cool city, and totally worth spending many days in - but it can't hold a candle to Machu Picchu.