Leaving 16 year old 3 weeks alone in summer?

I have a legal joint custody arrangement where the arrangement is 1 week alternating for each parent and in the summer we make arrangements for longer stretches.Kids are now 16 and 19 (arrangement no longer applies to adult child) and they have been living predominantly with me for last 5 years full time, their choice as other parent moved to another town 30 mins away.I have also shuttled them to most activities, appointments and part time jobs (no public transportation available).The kids visit their other parent occasionally, on weekends and this past summer youngest spent a few miserable weeks there when I was away on travel.This summer I want to travel for 3 weeks. Youngest won’t come as it’s boring and wants to work and I respect that. Youngest doesn’t want to go to other parent’s for 3 weeks because they will be far from friends and job (and I do understand that).They are mature to stay on their own at my place and adult sibling will be there as well as other family can check in.Q1. Can they stay alone 3 weeks? Or Q2. Am I selfish in wanting this break and forcing them to other parent? via /r/Parenting https://ift.tt/3nMWmKV