LMAO!
I am with Paul, maintain a constant speed up the hill as you are about to crest increase speed to the desired max with that max being about 5mph higher.
As far as mph is concerned, the slower the better mpg. The only way to really see improvement is to slow your roll. haha! Really, don't go over 55mph at anytime and you will be good to go..................yes, I realize it is not easy but those are the facts and you can do it, trust me on that
The max yield for me has been a P&G from 50-40mph on highways and 55-45 on interstates. I encounter lots of hills and I will crest at 50mph and coast on down to 35-40mph which ever I can get away with assuming the lower speed limit isn't 45mph.
OH, DO NOT USE A/C.