You won’t be able to find any public transportation going near the start of the trail to Pastoruri Glacier, so you will need to take either a taxi or a tour. Prices for both options do not include the 30 soles entrance fee to the national park. From the parking lot, it will only take you 40 minutes to hike to the viewpoint; but do not underestimate the effect of being at 5000m of altitude. Make sure you still drink plenty of water and take your time. Finally, the weather changes very quickly so bring rain clothes just in case.