I have a barn that needs some structural repair. I am toying with the idea of cutting the beams and doing the joinery myself. I am no huge hurry but want to try and do it right. How realistic is it that I do this all by hand with the right hand tools?

I have not yet attended any workshops but am interested in recommendations on books that show how these joints are cut. I am mostly interested in simple mortise and tenon joints to start with. I have reviewed some books online but I thought I would ask the experts...Thanks

here are three books:
jack sobon and roger schroeder -timber frame construction, all about post and beam building
tedd benson -building the timber frame house, the revival of a forgotten craft
steve chappell -a timber framer's workshop, joiner, design & construction of traditional timber frames

the first book is probably most relevant to barns.