You really are not going to get under 7 hrs. Pretty much impossible. Consider business class ( a few mentioned and you didn't respond ) or premium economy on ANA via Tokyo and West coast or Cathay Pacific via HOng Kong and west coast. Premium economy on these flights use a cradle rocket seat ( the person in back of you is not affected when you stretch out or get up, there is a lot of extra leg room , it reclines much farther than economy , had a little more width , on Cathay's A350-900 even the aisle seat side, next to aisle can open OUTWARD so you can get out of seat into aisle super easy. Note that not all legs may be premium economy on all flights but the long sections are for sure. Usually there is a food upgrade too. Round trips about $2300+ one ways $1250+ Kayak.com I find better than sky scanner. You can get from BKK to HKG to LA to Vegas in 21 hours. BKK to Tokyo to San Fran to Vegas 20.5 hours.