If you need cash flow, and the dividend doesn’t meet your needs, sell a little appreciated stock. (or keep a CD ladder rolling and leave your stock alone). At the risk of repeating myself, whether you take cash out of your portfolio in the form of “rent”, dividend, interest, cap gain, laddered CD…., etc. The arithmetic doesn’t change. You are still taking cash out of your portfolio. I’m just pointing out that we shouldn’t let the tail wag the dog. IOW, the primary goal is to grow the long term value of your portfolio, after tax. Period. All other goals are secondary.

Nobody gets early FI investing in bonds, CD’s, or even stocks unless they make a huge income or are extremely frugal or a combination of both. Paper assets just don’t provide enough returns. Business income can be great but it is typically not as semi-passive as I would like and there is a relatively high failure rate. That is if you can monetize an ideal to begin with. RE investing needs to be higher ranked IMO as a way that the “average guy” can become FI.

First: I understand why you would say that such investments are restricted to only accredited investors, because generally, that’s true. There are means, under federal securities regulations and Blue Sky laws in each state, to sell interests to non-accredited investors – but usually those means are so heavily regulated and involve disclosures so similar to cumbersome registration requirements that it is not worth it for the seller to offer to non-accredited investors.

Using ad networks like adsense doesn’t prevent you from targeting advertisers directly. In fact, that’s how I started; I searched the net for potential advertisers who advertised products relevant to my content and offered them yearly packages. If you choose this option, bear in mind that you’ll need to provide traffic reports and other site statistics.
However, this comes back to the old discussion of pain versus pleasure. We will always do more to avoid pain than we will to gain pleasure. When our backs are against the wall, we act. When they're not, we relax. The truth is that the pain-versus-pleasure paradigm only operates in the short term. We'll only avoid pain in the here and now. Often not in the long term.
If you have specialized knowledge in a certain topic, you can put together an online course to teach others. For example, if you have experience in real estate investing, you can create an online course “Real Estate Investing 101”. The benefit of an online course is that once you create the course material, you can sell it to as many people as you want.