In my own case, I found it extremely valuable to develop my game using (almost) pure JavaScript, using Dojo to facilitate some more mundane tasks (event publish/subscribe, browser sniffing, DOM manipulation) as well as adopt its AMD design methodology.
Apart from this, I've written my own sound, graphics, sprite and network-packet modules, and linked the game client to a node.js game-server (actionHero, to be specific). My own model is client/server, which differs from your mileage. I wanted to include that here to illustrate that HTML5 game development is entirely in the realm of "possible", if you're structured and using technologies available to you to make your development tasks simpler.
In terms of pure JavaScript, check out http://mobile.smashingmagazine.com/2012/10/19/design-your-own-mobile-game/ ... it seems to be most of what you're looking for. I don't have experience with PhoneGap other than to suggest to continue to look into it, as it seems to be the right direction to go for your intended platform.
The trade-off of going the HTML5/JS/PhoneGap (cross-platform capability at reduced performance) route over the Java/Android SDK (better performance, but limited to Android devices) route is fairly obvious, but is also worth mentioning here.