I would like to basically make a node with some tabs on the left that switch what's being viewed on the right. I can structure the content however I'd like since it's a node; is there a way to simply make the content display inside vertical tabs, like on the node editing forms, but when viewing the form?
Does the Render API allow rendering content in vertical tabs in a node?
See the Quicktabs Module.
If I'm not mistaken, Field Group module offers that.
See: http://dansilvercentral.com/jquery-ui-tabs-drupal-7-tutorial for an example.
Also, to facilitate easier implementation of this on a node-by-node basis, I have a custom module to add an on-site admin interface to choose which pages should get the library added to them, and I'm using Code per Node to be able to simply add the JS right on the page in the node edit form. I'd rather not have to keep adding to a custom module to support content being added and maintained on the site.
I would recommend Display Suite, which does precisely this (among many other things) with custom view modes for your content type.