2-week round trip England

Hi everyone, my son, who is 9 years old, and I, 35 years old, would love to do a round trip to England. Either in August during the summer holidays or during the autumn holidays. We haven't booked anything yet. The rough plan would be as follows: Flight to London. Day 1-4 London Day 5-6 Oxford Day 7-8 Bath Up to this point, we would do everything using public transport. In Bath, we would then rent a car and continue: Day 9-11 Lake District Day 12-14 Cornwall Day 15 Return trip to London This would be the rough plan. But it's still changeable. We are from Heinsberg, NRW (North Rhine-Westphalia). However, the starting point doesn't matter at first. Preferably in NRW. We would be happy to have some company. A mother with child or children would also be welcome. Best regards,