Having sat in the pilots seat I can tell you there's more room in your family car, it's a very narrow but deep fuselage.
The gun turrets are like wearing an extra skin, there's no room to do anything but turn with the turret.
The narrowness of the fuselage and the position of the radio equipment taking up the lefthand side of the fuselage makes the crossing of the wingspar a real challenge... you're looking at getting over a 2.5ft obstacle through a 2.5ft square hole with no ability to position yourself to the left or right of it, you just have to tackle it head-on.
Visibilty from the cockpit however is the best of any bomber, such a panoramic view. The propellor tip on No. 2 engine spining past a foot to the left side of your head I'd guess would be a bit unnerving.
As for whether you'd want to see action in one... I'd take a 4 engined plane anytime that after droping it's bombs could take the stresses impossed by entering into a corkscrew dive and generally fly like a fighter..
Regards
Simon