Creating a solar powered 'rover'

Think of this project as a mini-version of the sadly quiet 'Oppy,' the Mars Opportunity Rover.

What I want to create is a solar powered buggy -- on a smaller scale -- that runs around when it gets sunshine, then shuts down when the battery runs low. As with it's Mars-based counterparts, I would expect it to shepherd its resources when power is depressed, but it would be great if it charged an onboard battery well enough to keep an arduino powered up even through the night, so that it could respond to radio pings.

And, biggest ask of all, it would also be great -- in fact, required -- that it be able to withstand a full shutdown, but still get back on its feet again once it had collected enough sunshine to power up.

Has someone done something similar enough to get me started on the right path? Thanks.

Keep in mind that the microcontroller on an Arduino takes a lot of power to run - even my slightly used 9V battery couldn't turn it on (I'm using Uno Rev3).

I would anticipate having a fairly large battery pack -- say, 2000mah or more -- to shelter against the normal light-dark cycle. But the device would still have to be able to withstand going without over a rainy week. Or simply being hauled into a garage for an extended period, then tossed back into the yard with no charge whatsoever.

It needs to be able to rouse from the dead.

Lots of great ideas in this solar powered Arduino tutorial.

Some fascinating stuff there, including how he implemented the "watchdog" to reset the system after waking. Thanks!