Taking a loan out of your 401(k) is one way to do it. Another is the “self-directed” account which is discussed in the “Tax strategies” thread. If you take the self-directed route, talk to a tax attorney because there are lots of pitfalls. For instance, you can’t actually do any of the work in the park outside of high-level management decisions–if you so much as change a lightbulb you risk causing the retirement account to lose its tax-advantaged status. So that only works if you’re going to buy a park and hire someone else to run it (and I mean really run it, not just hire the on-site manager). You can also invest in "someone else’s park."Google “IRA prohibited transactions” and you’ll find a wealth of information.Finally, there’s a complicated tax maneuver with the acronym ROBS where you start up a C-corporation, put yourself in as the only employee, establish a 401(k) plan, roll your pre-existing 401(k) into the new 401(k), have the 401(k) buy the stock of your C-corp. In this way you can access the money and do whatever work you want in the park, but you’ve now negated the tax advantage of the 401(k) because the C-corp needs to pay corporate taxes.My advice is either take a loan out of your 401(k) as described by Charles, or set up a self-directed account and use that to invest with someone else who needs capital to buy a park.