I think somewhere between 62 and 65 is the sweet spot on mileage. You want to rund fast enough to carry the rollers without downshifting.
Definitely better mileage with the cruise control on. I don't know about other Newells, but I highly suspect that my DDEC is programmed like some of the fleet DDEC were programmed, in other words it has a higher power setting when using the cruise. The fleet owners do that to encourage the drivers to use the cruise. I swear mine pulls stronger in cruise.
And amen on the bike affliction.
I'm in Huntington WV, just off I 64 if you get close on your trip.
Richard Rhonda Ty and Alex Entrekin
1995 Newell # 390 DD Series 60, Allison World Trans
Subaru Outback toad
Often wrong, but seldom in doubt
Rhonda's chronicle https://wersquared.wordpress.com/