Red Diamond 372 Max Criusing RPM

I have a 1962 R185 with the 372, 5 speed overdrive transmission (0.823:1), 9.00-20 rubber and a 2-speed rear with a 5.57:1 ratio on the high (cruising) side. The engine is governed at 2850 RPM's. The way it's set up now I can run 55 MPH at about 2150 RPM's. I keep going back and forth about changing the rear end gears to something more cruise-friendly like a 4.88:1 (1900 RPM at 55 MPH) or even a 3.73:1 (1500 RPM at 55 MPH). I'm afraid if I go with the 3.73 that it will lay down like a dog whenever I get to any sizable hill. Does anyone have a similar set-up that works well as a compromise between speed and power? I may just leave well enough alone and stick with the 5:57 gears as I sometimes pull a trailer. Any thoughts or words of wisdom would be much appreciated.

Redk5guy