If you are using an 8' rod, it needs to be driven flush to or below ground. (8' of ground contact)
When I was looking, they generally left a little dirt out so I could see it and back filled later. If it was above grade, I loaned them my 2# hammer
I have seen rotary hammers used but here in Florida you could drive it with your Kleins.
#6 solid is all you need but I see #4 used to sidestep the physical protection thing. (Gets back to that "severe" damage thing) They typically bring it above grade next to the building if it is unprotected.
Protection is usually RNC if present.
If it is metal, there is an appropriate fitting that bonds the raceway to the rod clamp. Engineers will tell you high frequency transients will use the raceway and ignore the wire.
Typically the GEC passes through the first clamp and terminates at the second rod clamp unbroken along the way.
RNC or the afore mentioned metal raceway with appropriate fittings if it is not just bare solid, below grade.
