Not sure Steve...managed to avoid flying in B2's
...I was offered a few trips in em.
I am sure one of the aircrew will supply details for you,but it would probably depend on altitude,if the cabin is pressurised then the the 'Cabin Altitude' is lower than aircraft altitude,jet a/c have a cabin altimeter to confirm cabin altitude and hence to confirm if the pressurisation is working ok.
On the a/c I presently work on...I believe if the a/c is at 40,000' then the cabin altitude is approx 21,000'.
So I guess at lower altitudes one could move around easily as long as pressurisation is ok.
The stuff I emailed was mostly just for background info,sorry about the quality of the photos,I had more but cannot find them,but there are some nice pics on the net and will point them out to you soonish if you have not already seen them !
rgds baz