I don't get it. You're going to quit doing the job that makes you the capital to invest in parks? This is not rocket science @dominic730. I would say a theoretical grounding in the arguments for and against modern portfolio theory will prepare you for this - which you may already have. MPT vs behavioral finance is a debate worth becoming literate about - but since you are up for buying more parks it sounds like you've made your decision.
As for the dirty side of things - learning all you can about construction/plumbing/electrical will help as you go on so that you can have a literate conversation with your tradesmen.
Finally, some basic financial modeling skills are helpful because parks have a somewhat complex capital structure - with several different discounted cash flows to build out to arrive at an NPV you can use to compare one park to another when in the buy phase.
Negotiation skills are useful anywhere in life but especially in parks during the purchase, operations and disposition phases. Negotiation with sellers, tenants, tradesmen, buyers, employees.
Love of reading helps - consuming all the info you can from great sources like Frank and other industry leaders who enjoy teaching.
A love of organization is helpful if you intend to do turnaround parks and manage a lot of rehab/remodel projects. There are software tools now built for these tasks such as buildertrend.