I never ran 33's with my 4.88's but the gear swap definitely was noticeable with my 315's. I can cruise along at 65 MPH and 2600 RPM on the interstate pretty easy depending on grade. Towing is way better. I rarely have to use 1st gear now on the hills
Like you I don't see 65+MPH often. There is not an interstate for hours in any direction from down here.
The one thing to keep in mind though is after 3200PRM your MPG is going to drop considerably due to fuel management. So what ever speed that ends up being will kind of be your top end for cruising on the HWY without massive fuel consumption.
Wheeling in the rocks offers more control.
I still want the SC or a turbo.