LS1 '48 3100 swap, rpm range, few other questions

[Dustint]

Swapping a LS1 out of a 98 z28 into my '48 3100. My first question is regarding gear ratios/rpm etc. I plan on doing a mild cam, and would like to figure out where rpm would like to be when cruising for somewhat decent fuel mileage.
Using a calculator a 3.50 rear end ratio (currie 9'') would put me at 1773 rpm @65 mph (highway speeds in area). 3.25 would put me at 1647 @65, and 3.70 is 1875.

I've driven the camaro, and it has a 3.23 rear end, so the logical side of me says that would be the way to go, much more than that would probably be just spinning tires anyways due to low weight of the 3100. My question is though, would this be okay with a mild cam? I know that a non stock cam will like a little higher rpm while cruising, but not sure where that line is. Only number I came across was above 1700 is good with a non stock cam. Can anyone support this? I'm thinking 3.25's would move the truck along pretty quickly, and much more may be overkill with little weight in the rear and would be best for fuel mileage, but don't want to have too low of rpm for the engine to cruise also.

Beyond that for now, as this will be my first ls swap, does anyone have any recommendations on fuel/and or cooling system and wiring, etc.