HighClere Castle Full Day Trip

I don't know if this would help you, but I booked Brit Movie tours for the Downton Abbey tour for this May. It is the Downton Abbey and Village Small Group tour by Mini Coach. There are two tours, the small tour and the large coach bus tour. We will have a guide and I booked the small tour.

Look them up on the website for Brit Movie tours. If you do decide to go with them, do book early as they do fill up.

It should be wonderful wheather you go on a tour or on your own.

It's not clear if you are aware that the 2 locations are nearly an hour apart, so doing both might require an inclusive tour. I didn't go to Bampton, but went to Highclere by train and taxi from London.

Highclere Castle is only open to the public on a few specific days, and it fills up quickly as soon as the dates are announced. If you sign up for a tour with a third-party tour operator (not with Highclere Castle itself), the tour operator is responsible for making sure Highclere Castle will admit your group on your chosen date. Here are the announced dates for summer 2020.

https://highclerecastleshop.co.uk/categories/summer-2020-admission-tickets

And here are the dates for a tour that includes afternoon tea.

https://highclerecastleshop.co.uk/categories/castle-tour-exhibition-gardens-and-afternoon-tea

I'm not sure what you mean when you say you want to walk around "the villages." Highclere Castle is in the southern outskirts of Newbury, a sizeable town that is not particularly quaint and is not (AFAIK) used for village scenes in Downton Abbey. Walking around outdoors at Highclere is possible; see

https://www.highclerecastle.co.uk/where-can-i-walk

Bampton, as others have pointed out, is in an entirely different place.

I did this as a guided day trip in Sept 2018 and it remains a very cherished travel memory--HUGE Downton Abbey fan--not only did I get to see Highclere but other places I wouldn't have gone on my own as all 3 locations are about an hour apart. I booked through Viator and it was perhaps $165, started at 7 am and returned to London around 6 pm. We travelled by big comfy bus with maybe 20 people total, excellent & very entertaining and knowledgeable tour guide. First stop was Cogges Manor Farm (Yew Tree Farm in the show), a beautiful working farm where we spent a couple of hours exploring, then to the charming village of Bampton to tour the church and explore for perhaps an hour, then finally to Highclere around noon, giving us a bit over 4 hours on our own to tour the house and grounds and have lunch--great food options. It was a warm day and at the end just really nice to sit under a tree with a cool drink and admire the house and gardens.

I bought Highclere Castle Tickets for April 2020 but they don't issue refunds, even due to the pandemic we had to cancel our trip. They offered Aug 2020 or Spring 2021 tickets but I don't know my travel dates yet. I'm trying to get a refund or credit.