I would like to put a sub panel 800' from the main panel.
I have 2 hots and a ground. Would like to know if I need to drive a ground rod and treat it as a separate service with 2 hots a neutral and a ground

Consider calling a professional... you will need to do some homework
Before this project is successful.

Well the simple answer to your question is that you need to install a complete grounding system at the remote building.

Then you will need to bring a four wire feed from the main service panelboard to the remote building.

At the remote building, the incoming "Neutral" cannot be bonded to the remote panelboard.

At 800' you may be in a cost prohibitive area. For example, if you want to bring 60 "Working" amps to this building you would need 4/0 copper conductors. I have no idea what the cost would be in your area but I'll bet it isn't cheap.

Aluminum is certainly less expensive than copper but still it would be a big hit dollar wise.

You might be wiser to see if the POCO will set up a nearby transformer for you or look into solar power.