So, how should I clean this thing ? My thought is to
simply open it up
and hose it down to get any crap out of its box,
I think that you have the correct idea, wash it down well, let it dry a few weeks, then
give it a try.
As long as it wasn't turned on while wet(or was busted before being tossed out) it
should work.
Most electronics can get cleaned this way(except things that the water can't run out
of properly like hard drives, etc).