You can see the space I had to crawl through. The Canadian Warplane Heritage Museum offers flights on many of these aircraft and in the B-25 and Lancaster once you're airbourne you're allowed to craw about the aircraft inflight, including the tail gunner seat.
And you have to visit the fantastic gift shop. I liked this lego knockoff in Ukrainian colours.
And I bought Robert Stanford Tuck's fantastic book Fly For Your Life in the used book sale. This was the very first, autobiopic non-fiction air combat book I ever read - I bought it new in the early 1980s when I was about 11 or `12 years old. The first few pages of this used copy brought back some memories.