Visits ending too late

We have been trying to figure out our FS5s visits based on mom having rehab in the mornings and him going into afternoon Kindergarten. I was very firm that he had to be home by bed time - which is 8 - luckily for us mom doesn't sugar him up and he is always exhausted so he would go straight to sleep. I also am firm that I will not transport in the evenings or weekends since the other kids need to be places and if they want me to transport - it has to be between certain hours of the day. They asked me to move him to morning K and I said no b/c then I lose busing so unless they want to drive him everyday that wasn't happening. Then they asked weekends and me to drive and I said nope - we do sports and other activities and I can't commit to that. So then they came up with a plan to pick him up from school and limit mom's visits to 3 hours instead of 4. Now she is in jail so it doesn't matter but I have found you just have to stand firm. Tell them no over and over. I know I am a good home and they would never move him so I don't give in to things that will affect him or me or my kids. I wish I could stop visits all together...but that's a completely different story ;)