Family driving trip - costs per day?

We'll be landing in Aberdeen, driving through Huntly to Culloden to Glasgow to Stirling to Newcastle and ending in Leeds. What's a low- to mid-range budget per person for daily food? We'll probably stop somewhere to eat nearly every day, out of curiosity, but we'll carry bread/cheese/snacks/fruit etc. We found so many easy pubs along the roadside in Ireland to get a Guiness and an easy bite -- is it the same in Scotland and England? Thanks in advance!