As a backpacker by trade who is slowly converting to touring I think I understand your dilemma. When backpacking I use a distance measurement I call "Equivalent Miles". On relatively flat ground I have a speed that I am comfortable and at that speed I can make a mile every 20 minutes. As the ground inclines or declines I will shorten my stride accordingly but my pace will remain the same, that is, I will take the same amount of steps it would have taken me to complete a mile on level ground - an Equivalent Mile.

So I'm not really concerned with map miles as I am with Equivalent Miles. And that is how I measure distance and pace. I can go for hours and hours and hours as long as I maintain the same comfortable pace.

My problem is converting it to touring. One thing keeps throwing me off - downhill. While backpacking I still have to walk downhill (not so easy as it sounds). While on bicycle it's a free ride.