Dan,
I was working part time in a park with buildings from the midstone age till about 1415 AD.
My 'job' was ropemaker, and since the ropewalk was next to the house from 800 AD that was my time.
For some photos see:
http://new.photos.yahoo.com/willeke_igkt/album/576460762346831529/photo/29492880... and following.
I did it only one season, it was hard to do it, next to a full week's work, the park being over an hours travel each way.
So I was mostly in the open shed, making rope with the visitors, the rest of the time I would be in the house, but I could never leave a fire there, it would be unattended whenever I left the house, and being at floor-level all kinds of dangers could develope......so I would only make a fire in the coldest weather, me being sure to be in the house most of the day, rather than sitting out in front of it.
Magnifying glasses I have used too, but never more than scoring a hole in a piece of paper.
Willeke.