Dave,
I've used the (Google) My Tracks apps for recording where I've been. Super simple to add waypoints as you are going along the route. When you come back to someplace that has a network connection, you can push it to a Google Map in your account, or just save it as a .kmz file for Google Earth (In case you want a record of your hike, for instance)
My impression is that it will continue to draw a "path" of where you've been, even if there is no "map" data available because you can't get a 3G/WiFi connection - so you can't see "where you are", relative to a map, but you can certainly estimate relative hiking distance, and whether you need to go N/E/S/W to get back to where you started. Obviously, if you are connected to a network, you can see a map or satellite view.
If you are walking, you might want to change the sampling time settings to sample the GPS receiver infrequently, and put the unit into Airplane mode to save juice.
I would experiment it to see if that satisfies your needs - I just put mine into airplane mode, and fired it up with some previously recorded tracks. I can zoom and pan around and click on waypoints to observe their name and any notes i added.
It's not an offline map system - but if you are comfortable with that, it's a free solution.
Happy trails!
eu1