My buddy Dave asked what I would recommend for his first purchases on his Gen 4 Prius, here are my thoughts on his must have’s!
First things first, a trailer hitch and inverter are the first things that come to mind. Many like the Renogy 2200W 12V PureSine Inverter.

Once you have power and the ability for more storage, you need a trailer hitch rack and a stabilizer! I don’t have one but still recommend a hitch riser, especially if you have a 2″ hitch cargo rack.
I love my hitch mounted cargo carrier but many other have chosen a lower prices version here.
All of my recommendations can be found below. After these are installed you should be ready to really experience Overlanding in your Prius.