Green Horn you are doing exactly what I am just finishing. Brad has a some very good advice. Use Steve's book. I took his workshop, which I also highly recommend if this is your first t-f. I am also a mech engineer and recognized a lot of the calculations Steve uses. However, I did not do every load calculation for my home. Steve has already done them for you. I had a lot of the same spans that were used on the plans in back of the book (roof, 2nd floor, etc...) That took care of alot of the design work.
Secondly, when I thought I was done with my design I took it to a local timber frame shop and got some advice. I ended up redesigning my frame 3 times. Take your time in the design process, there's a lot to think through especially when you get to wall systems.
Lastly, if you're going to have a construction loan and build it yourself be aware that everything about a t-f home takes longer than a traditional stick built..... right from the footings up.
