England and Scotland Itinerary

Lake District is definitely difficult to do without a car. None of the major Lakes towns have railway stations, the nearest being Oxenholme, which is not a major station. Nearest major station is Carlisle, which isn't exactly close.

As for the Wall, the eastern side of it is also difficult without a car, though I can't speak for the western side (which you'll be closest to if you're coming from the Lakes).

I'll have a go at answering your questions.

All else being equal, I'd follow the September weather from north to south -- fly open jaw to arrive in Glasgow or Edinburgh and depart from London.

Trains and buses will take you most places, but a car gives you much more flexibility to travel at your own pace and go where you want. I believe there's an age limit of 70 -- meaning that you, the younger spouse, would need to do all the driving. But your husband can be the official navigator!

For best value, simply rent a car once you leave your first major metropolitan area. For example [edited to reflect the north-south progress], start out in Edinburgh using public transport for the first couple of days, then get your car from the airport and be on your way to St Andrews. At the southern end, enjoy the Cotswolds, turn in your car at Heathrow, and enjoy your last couple of days in London without a car. In other words, don't mix renting a car for a couple of days with taking a train to another part of Great Britain, then renting another car, etc.

The Cotswolds, Lake District, and Hadrian's Wall are all best accessed with your own car. Personally I wouldn't care to pay for bus/van tours to "the more remote areas."

Blair Castle, St. Andrews, and Dunkeld are very accessible by car. Invest in a decent map or do some thorough online map research before you go. Parking in St. Andrews proper is rather limited and not free, but follow the signs and you'll be all right. Most places in Great Britain that are popular with tourists seem to have a pay-by-phone option for parking.

If you go on TripAdvisor and look up "Things to Do in Dunkeld" you'll get plenty of ideas.

Invest in a good guidebook, either Rick's or some other. The cost is negligible compared to how much it will save you in avoiding mistakes and boosting the chances that your trip will be really fun and hassle-free.

Rick Steves books discuss options for public transport in Cotswolds and Lake District-they are limited but an option.

Thank you for your replies. I am looking into open jaw flights beginning in Edinburgh. I am also getting more comfortable with driving which may be best for us after all.

The only problem with open jaw is that at least right now, the airfare is really high compared with Detroit to London round trip.
But I have a travel agent looking.

If you have time to answer, how do you recommend I fit Bath into the scenario where I rent the car in Edinburgh?

In answer to your question about Bath, you could make it your last stop as you progress from north to south, and return your rental car there. There's convenient public transport from Bath to London. You'd book your rental car for pick-up at Edinburgh airport and drop-off in Bath.