My husband and I just returned from our trip to England and Scotland. We decided not to drive, but took trains, buses, and taxis, and did some walking in the Cotswolds.
Thanks to all the suggestions here, I did the following:
1. Bought my tickets in advance and saved a ton of money. For example, paid £25 to go from London to Edinburgh on Virgin Train East Coast. Learned on this forum about when tickets go on sale and how to sign up for alerts.
2. Changed my itinerary between Bath and London (and glad I did). I was originally going to take the train from Bath to London Paddington, then take the Underground to Kings Cross for my next train to Edinburgh. Since I only had an hour to made the connection between Paddington and Kings Cross, I decided to get to London the night before to give myself plenty of time to get to Kings Cross. Turns out, the train that I had tickets for was cancelled, and the next train didn't come for another hour. Wouldn't have made that connection if I hadn't changed my plans.
We took four trains on our trip, and only one ran on time. Two of the trains we had tickets on were cancelled entirely, and one was an hour late arriving at the station.