Hehe, been there done that. In fact, doing that, right now I'm fixing a window frame that had 'a small spot of rot', by the time it was done half the frame had been removed, incredible how bad wood can be under nicely looking paint. Insect paradise underneath there.
is similar to "a small spot of rust" I guess, there is no such thing :-)
Fascinating to see how these old tree constructions are made. I still find it hard to comprehend that a few bricks and some timber logs are all that separates me from living directly on the dirt like a cave man..
Sound like fun, and you shouldn't let age stop you from doing that. Instead you should adjust your dream to building a smaller post-and-beam house. It's not back breaking work if it's a small house; our inner cave men wants to work with timber for some reason.