The flight from NY to Hawaii will take 60 x 11 + 20 = <<60*11+20=680>>680 minutes.
All the activities will take 120 + 240 + 30 + 40 + 70 = <<120+240+30+40+70=500>>500 minutes.
For his nap, he has 680 - 500 = <<680-500=180>>180 minutes.
To convert minutes to hours, he has 180/ 60 = <<180/60=3>>3 hours.
#### 3