What's the best way to transition from commercial to residential?

That sounds like a great game plan. Commercial is so interesting that you might find you actually like it better. At the very least, it will give you a good background for understanding both industries.
If you want to go to residential, here are three tips:

1.) Continually read the real estate pages, where there are plenty of stories. The local daily papers and the Business Journal usually write a lot about who's who in real estate because they are big advertisers. Jot down the names of the people in those articles and make a point to remember them.
2.) Go to local industry get togethers/cocktails like those sponsored by the Chamber of Commerce. You might meet some of these people. Make a point to make 2 new acquaintances at each meeting. Start your own address book (rolodex for old-timers). If you go to one such meeting a month, you'll meet 24 people over a year, or almost 50 within two years. Keep in touch with them through phone calls or Linkedin. Let them know you one day might want residential if the right offer comes along. After 10 to 20 years in an industry, you'll amaze yourself by your knowledge of who is who in your county. And also volunteer at these chambers, which are superb at networking.

3.) Memorize the names of the top 5 residential developers in your county and their CEOs. Business Journal usually has a list of the top ones in a county. That way, if you meet executives from that company, or even the CEO, at one of these industry meetings, you can introduce yourself. Then if a newcomer comes along, you can judge if the newcomer has potential.
Remember, CEOs are always looking for young talented workers for their companies.