Re: Advice on Starting STEAM Related Classes
For teaching programming, consider the AP Computer Science A path. There are plenty of established websites such as edhesive and CodeHS which have predefined modules that will help you and your students learn effectively. After taking the course this year I am confident in my programming skills and believe it to be one of the best ways to introduce students to real programming.
For Engineering, specifically CAD, I've heard great things about the PLTW curriculum and its specificity in teaching Inventor. There is also predefined curriculum for Onshape, if that's something you specialize in.
Make sure your school already has a position for a teacher that specializes in not only teaching but has prior experience in either or both of these fields. As a student who has experienced good teachers with no industry experience, good engineers with no teaching experience, and people who have both - it pays dividends to wait for the right person. Obviously these are school district level decisions, but the desire to push for STEAM programs in your local area schools is entirely up to the community.