I officially finished everything in Point Lookout and then got stuck into Mothership Zeta, I forgot how completely herp derp, bat**** crazy the plot is, being led around a spaceship by a ten year old girl who can rewire alien technology, at least I do enjoy it as a mindless slaughter, the logs are fun too.
At some point before MZ I took the perk which reveals all the unvisited locations, was quite disheartened to see a few places I don't think I've ever been, if I really want to consider Fallout 3 put to rest I'm gonna have to check them out