OsmAnd performed quite nicely when I crossed the US west-to-east. The cartography is mediocre, but the app's feature set is excellent, and the data quality is quite good. You can download entire states or countries at a time, roads-only or with points of interest, and optionally with hillshades...
As you may have inferred from the name, Bolivia’s Death Road is no laughing matter.
Thousands have lost their lives on this notorious mountainous highway, including over a dozen tourists since mountain bike tours became a thing.
A hydration pack is not a necessity, but it is very convenient. There are also “drop in” hydration systems such as the Camelback Unbottle that can be used with nearly any pack. So there is no need to buy a specific hydration pack. The Unbottle and similar systems make every pack a hydration pack.