Changes

Buses are expensive but unbelievable nice. Fully reclining seat and food provided. If you take a bus, treat it as a hotel and save a night's hotel fees.

Trains are super cheap but only serve limited routes. They are an excellent way to see the countryside and come in contact with a different segment of the population than you'd encounter on a 1st class bus. Highly recommendable.

In the cities you generally need exact change (coins, no paper money) to pay your fare, so hold on to those 1 peso coins.