New rear gears for 65 230 manual, suggestions?

[Old65C10]

I just bought a 1965 C10, 230, 3 speed manual long fleet.

I love the truck, but on the road, anything over 60 MPH it really seems to be spinning at a high RPM. It feels like I am really pushing it.
I have no plans to do any heavy hauling, I have a 85 K30 for that. I just want to be able to run to the store etc. Where I live the speed limit is either 60 or 70. 60 is OK, but 70 it just won't go there.
What ratio would you suggest I re-gear to? It is a 65 so it should be the 12 bolt. Should I look for a good used rear from a 67-72 with better gears, or just re-gear the rear I have? Anything unique about the 65 12 bolt?
In the end, I want to use the C10 as a car, and save truck duty for my K30.