Great ideas for breaking up the journey.
Depending on if you decide to break it up both directions/ whether your children are good car sleepers - I really recommend driving down at bedtime so they sleep in the car.
We usually do early dinner, bath time, put little ones pyjamas on then hit the road before 7pm. Means we get a peaceful journey, unload and into bed before midnight. If you're self catering most places have key boxes now so doesn't matter too much what time you arrive...
Anyway just a thought! Have a fun holiday