S.F.
I always liked the routine my babysitter as a kid had for all of her charges. Once we got home, it was snack time: piece of fruit and a sweet. After that, homework. No one left the table until homework was proven to be done. After homework, we were allowed to play outside, practice our dance lessons or music lessons, work on a craft project, listen to music, etc. As you can imagine, on the longer days, we played outside until we were picked up. On winter days, we were doing crafts or baking.
I've tried doing this with my family, despite ragged afternoon schedules, two jobs, etc. It works fairly well. I think in your case, the snack at 4pm would tide your little ones over to dinner with hubby at 6pm. Not sure how much homework a 5 year old has, so that might be a good hour for some safe tv. I know I used to show my kids old musicals or old Disney films (stuff from the pre-Beauty and the Beast era). "Singin in the Rain," "Bye Bye Birdie," "Sword in the Stone" and "Many Adventures of Winnie the Pooh" gave me and the boys something fun to sing and dance to as I prepared dinner and got a load of wash going.
Today, at 12 and 16, we still have pretty much the same routine, although I discourage tv during the school week. Too much racket and it creates way too much lack of focus.
I've found routines to be very comforting and I think they make life easier. It's nice to know what you have to do on the days when thinking is hard.
Good luck!