They took the map caching feature out of Labs in one of the recent updates a few months ago, so you can simply select My Places from the navigation dropdown and then swipe to the offline section to cache some maps. It is still a little wonky though since Google Maps is so dependent on network connectivity for everything, so I tend to open the offline maps while I still have a wi-fi/3g connection just to make sure it loads properly.

Who makes the "Navigation" app that I've found on every Android phone I've used? It's been quite useful without a data connection for a daily commute. (It probably would not survive a trip to another city.)

Navigation is a Google app designed specifically to interface with maps. It seems with the new iOS maps they have just build Navigation straight into the app.

It would survive a trip to another city. It caches your whole route. It just won't make any changes on the fly if you go off-route while offline.