san isidro trail
San Isidro Trail I thought it was only two hour walk, so I didn't bring much water.
The trail starts from the plaza of Iruya (behind the church, where Federico III Hostel is), there is some pig pens, if you can't see it, use your nose. Walk down the ramp and cross what should have been a beautiful waterfall (but it was filled with garbage). Go through a pass and follow the road from there.
The first part is easy, just stroll through the village... but then the trail lead to the left of the valley, you then have to fork through many little creeks, if you don't mind wetting your feet, then it is easy, else you have to figure out the point of forking for each little creek. It took me 4 hrs to get there, the road ends when you reach San Isidro. You have to climb very steep stairs/ramps to reach there (so save some energy at the end). There are two ramps going up (both on your right hand side), choose the 1st one, the 2nd one goes nowhere. You will see a pretty church there, and they do sell bottled water there, so refill for the trip back. It took me 4 hours to go there (it was a hidden elevation), but only 1.5hr to return (when I refilled myself with water).