What you are refering to is actually called the "virginia tuck" where you would use a IWB, but leave the exposed part of the firearm visible. Yes, this is legal as OC.
Yes, you can OC even though you are from out-of-state.
as far as resurants/bars/clubs etc, you have to open carry in these locations. As with all private property, they can ask that you leave it in the car, or ask you to leave.
You can drink (just not be drunk)and open carry, but I dont think anyone on here would suggest it. I would also be willing to bet that the bar wont be too OC friendly.
Hope this information helps
**edit for spelling**