I like the Waterville-Madison route the best. It seems slightly more direct than the Augusta-Farmington route. 99% of the drive is between 50-70 mph....depending how fast you go on 95, of course. I can make it to the Loaf from Portsmouth in under 3.5 hours, with a 10 minute stop at a store. Can't seem to get there fast enough.
That's the way I go, 65 minutes from Rt 95 to the loaf. I can make it in 3 hours 5 minutes from Lee if I get on the pike in Wells.