I find, just closing my eyes works fine for me. Try it, and you will find it is dark inside with the eyes closed. LOL :) Same process I use for taking an after lunch nap, in my recliner here at the house. Have lunch, set in recliner, beagle curls up in my lap, we both close our eyes and soon we are asleep. Daylight and not a problem here, so why would it be elsewhere.
The big problem I have in the north is deciding when to go to bed. I learned over the years to go to bed when I got tired. Hardest thing was to get the daughters to go to bed in the summer time when we lived in Nenana. One night my wife woke me up about a noise she heard outside the house. In checking I found both our daughters, dressed and playing in their tree house next to the deck. They were not please to have to put their PJs back on and go back to bed.
Most of the north country functions on this time schedule of going until you can't go anymore and then crash. Works great if you don't have to be to work at a specific time as most urban residents have to do.
Never heard of anyone that has died of lack of sleep, unless they were driving their RV/car or flying an airplane and decided to go to sleep. Part of the fun adventure of RVing in the north country.