Oh my goodness. So your Dad says that taking a date on a 20 mile hike isn't such a good idea, and that showing off in this fashion isn't the best plan?
I'm laughing my head off here...reminds me of my husband taking me to Arecibo Observatory in Puerto Rico.
http://www.naic.edu/
I remember my husband being so pleased with himself, taking me to this 'cool' place - it's just that I had to hike umpteen stairs to get up to the thing in 90+ F humid weather. Piece of cake for him, a *challenge* for me (at the time).
Um - don't take dates on overly challenging hikes/adventures??