I'm fortunate enough, at my young age especially, to live my dream job racing cars all around the world which keeps me busy most of the time.

At 60 years of age, I imagine myself holding a pile of deeds, not a mountain of new loans.

@Brandon MorylYou can actually contribute up to $53k to the Solo 401k for 2016 ($59k for participants over age 50).

(Age of property?

Helpful regardless of the ages of the occupants.You may want to have a candid conversation with the parents about your interest in child safety and ask them about their thoughts.

There are plenty of people at retirement age who do not have $500,000 liquid (or illiquid) on their personal balance sheet.But that 28 number has a downside ... you have a long way to go in your life and lots of things can happen in your personal life and in your real estate business that will alter your business and goals.First, to earn $10,000 per month ($120,000 per year) on $500 K is a 24% return ..... possible BUT you probably can't count on that much return EVERY year in any investment (OK ... somebody will dispute that assertion).I suggest that your (soft) goal for the next several years would be to double your capital to $1 million by doing what has worked for you.  

You are making a good decision at young age.

Also, is there anything I can do and invest in since I am such a young age.

Here's an article about a woman who "rented back" an apartment at age 90 and wound up outliving the buyer.

This was because those two heirs were the only people to help the parents as they got up in age.