We travel between 70 – 74mph on the Interstate and this is equal to 2100 RPM. In a 13 hour day, we can travel 800 plus miles. At this speed we still get 10.25 mpg. In my opinion, you need to drive at what you feel comfortable.
Just came off of a 2872 mile round trip from OK through AR/LA/MS/AL/GA/FL/SC/TN/KY/and MO.
Open hiway speed limits changed from 55 to 75 depending on each state limits and hiway type. I don't have a set speed as terrain and driving conditions/heavy or lite traffic change. However if terrain and not many folks on the road I may drive 75 mph legal limits. I drive any legal speed I'm comfortabe with.
Having a construction business years back with a 1 week-2 week turn around between jobs and maybe a 600-800 mile run to the next jobsite with several trailers on the road, I found out a long tome ago which tires on my trailers worked and which didn't work as advertised.
"good judgment comes from experience, and a lot of that comes from bad judgment" ............ Will Rogers
'03 2500 QC Dodge/Cummins HO 3.73 6 speed manual Jacobs Westach
'97 Park Avanue 28' 5er 11200 two slides