I got approved for 765k and I am currently looking to see if i can acquire a fourplex.

In order to grow your portfolio you should acquire more properties.  

This will allow you to acquire more rental units and also being able to use the vacated unit rents at 75% to help your debt to income ratio DTI.There is a FHA 100 mile rule if you do plan on using FHA on your 2nd house hack.

Who all has ever acquired a property and built an RV park?

It seems that the next best thing is to acquire directly from sellers.

So given all this info (and again, these are genuine questions - I am not trying to goad anyone here, I am genuinely asking for perspectives on this) - how do you acquire property?

As Dave mentions, you can sell the newly acquired property at any time. 

For me, I only acquire rental property for cash flow.

It has allowed me to gain wealth faster than renting, but now I find acquiring the next property very daunting.

In a 1031 exchange, you need to use your funds to acquire/improve property that you do not already own.