Drew:
I can help you on both questions.
Dietrich's software is designed for doing timber framing. However it is not for the average home user. It is a professional program, and we can discuss the details.
Send me a private email.

I use this program to do drawings, for myself and others.

About the permit office, you should/could have a before hand chat with them and ask them what they will need to ok a set of plans. If they want them reviewed by an engineer, so they feel safe with ok'ing them then we can help you find an experienced timber framing engineer who is licensed in your area and can help you by reviewing and advising you about your design/plans.

Jim Rogers

PS where are you located?