I would go with option 2 - quieter but hillier (the Chilterns)! Do that a few times a week and you'll have calves like rocks! Another option would be to take the slow train and get off halfway. I hope you have some serious lights and reflective stuff - when I still lived in London, I did Oxford to Didcot after work many times - can get pretty hairy in the dark - potholes and fast drivers. Stay safe
I would go with option 2 - quieter but hillier (the Chilterns)! Do that a few times a week and you'll have calves like rocks! Another option would be to take the slow train and get off halfway. I hope you have some serious lights and reflective stuff - when I still lived in London, I did Oxford to Didcot after work many times - can get pretty hairy in the dark - potholes and fast drivers. Stay safe