> start incorporating DUP and OVER and ROT and PICK and friends

If one understands adding and consuming values at the top of the stack, putting the stack in the state you want it is certainly a small logical step without new theoretical baggage.

Word definitions and the accompanying pointer tricks are more likely to be challenging.

The stack is functionally very simple, but keeping a mental model of what exactly is on it at each point in your code and how to transform it to perform the calculations you need can be tricky.