What is your background, career-wise? I know you mentioned HVAC, are you an independent contractor/small business owner, or do you work for a larger company? Making great beer is one thing (congrats on that by the way, that's an impressive resume you have going), but ultimately, running a brewery is a BUSINESS, not just making beer on a larger scale. As it sounds like you're beginning to realize, there are a ton of aspects to consider besides making good beer. I'd venture to say that good beer isn't even the MOST important aspect of having a successfully brewery, judging by the number of breweries around me that seem to be successfull and expanding despite the fact that, IMO, they're only producing mediocre beer, at best.
When you talk about keeping a full time job and brewing twice a week, some things to consider:
Who's doing the bookkeeping, both on the accounting side as well as regulatory? That's a big part of running a business.
Capacity planing and material ordering - you need to know how much beer to brew and when, based on what's selling
Speaking of - who is going to sell your beer? Are you going to have a tap room you have to staff, are you going to self-distribute (if allowed in your state), are you going to negotiate with distributors and get out and talk to bars and liquor stores to make sure they are going to give you tap/shelf space? Make appearances at local brewfests to pour beer?
There's a lot to manage and understand and track. As you're seeing, a business plan is a big first step. Go to a bookstore and get a book on small business planning if you need to. Think through things one at a time and make notes, familiarize yourself with all aspects of business and be realistic about how you will manage everything (and how much you can manage yourself vs. hiring help). Review your local and state laws for liquor licensing, zoning (even places that allow small businesses just about anywhere can get pretty restrictive if you start involving alcohol). Put together a high level startup cost list and cash flow plan to see how/when you can actually start paying yourself, and see if you can make it work.
Some breweries will accept volunteer help, but be forewarned it's not going to be brewing. Cleaning out and hauling spent grain, washing floors, washing bottles, maybe washing kegs, basically all the crap work no one wants to do. It will be on you to keep an eagle eye on what's going on around you, ask lots of questions, and use that time spent doing crap work to absorb as much data as you can to make it worthwhile.
