Backbone may or may not be right for you. Fortunately it's small, and fairly easy to read. The annotated sources [1][2] for BackBone and Underscore are fairly accessible.
Also, I would highly recommend adding an AMD loader like require.js to your "basics kit". Code organization gets very important very fast, and it helps to think modular-and-reusable from the beginning.
[1] http://underscorejs.org/docs/underscore.html
[2] http://backbonejs.org/docs/backbone.html