Toilets: There are a few toilet tents scattered around the base camp. they are basically a hole in the ground with a tent around it, but it beats sitting in the open with the cold wind around. Some of these are also private belonging to the trekking companies, these are locked.
Water: The Park rangers have arranged a few water pipe lines from the river into the camp. These provide nice clear water for drinking and cooking.
Food & Drink: It is possible to get both food and drink in basecamp:
Dinner: $15 - Sallad, meet and juice to drink
Coke: $3
Beer: $2
With reservations for price adjustments...
Glacier: About half a kilometer from Plaza De Mulas is a glacier. This is great fun to play around in on a sunny day, and gives great oppertunity to get nice photos.
Playa de Baja: Between Plaza de Mulas and the glacier is a little lake. in the mornings it might be covered with ice, but it is quite nice to take care of some hygiene here (a bath).