Kew Gardens and Windsor

Not to do both justice - especially if you are planning to go round Windsor Castle.

I haven't been to Windsor, but I cannot imagine doing that. Kew Gardens is huge.

A better plan would be to visit Kew Gardens and then see Hampton Court Palace since they are close to each other.

I also agree with the previous responses. Windsor and a brief walk across the river to see not much of Eton was pretty much a full day. Kew is indeed huge and I am a big garden guy so it was all day for us. We took the boat back to London and that was nice. The folks in the gift shop at Kew helped us out as I recall. We enjoyed both outings. Safe travels.

Kew Gardens is less than a half hour on the subway from central London, you can go anytime, even in the evening. There are fairly inexpensive package day trip tours with pickup in London of Windsor Castle and Hampton Court Palace together, which is a good combination. I took the train one way and a boat the other way on the Thames to visit Hampton Court. Windsor and Hampton Court are around an Hour each by train from Central London. It would take another hour to take a train between Windsor and Hampton Court on the train.

I know that some folks have short vacations and try to fit as much as possible into each day of sightseeing.

But all of named places are miles from each other, and are each very large and quite expensive to visit.

We are members at Kew Gardens, know it well, and have favourite spots. On a quick visit we will usually walk 2 or 3 miles and be there 2 or 3 hours. If you are new to Kew Gardens and want to visit some of the specialist buildings, such as the huge water lily and the alpine house and the two massive glasshouses, and get around some of the more popular places it will take most of the day and you will be tired.

Hampton Court Palace has been mentioned as an alternative. Members there too, and there you have a large palace with many rooms to see and visit in several different periods, including Henry VIII's kitchens with actual meat roasting, 3 large courtyards, and acres of fabulous gardens, wilderness, maze, the Great (grape) Vine which has a whole apartment to itself (biggest anywhere). The gardens mirror the different periods of the Palace. When we visit we usually there around 4 hours, and we leave because we are so tired.

Windsor Castle (can I presume that you are asking about the Castle, and not asking about spending the day as well in the town and across the river at Eton) is another big place, and the most distant being the only one not covered by Oyster within London's zones. Having been a member in previous years I've been there several times, but not for the past 3 years. St George's Chapel is full of visible history, and is the end where the changing of the Guard takes place along with a military band. The tour through the Castle is quite long but actually only covers a small part of the Castle because it is, unlike the others, still lived in. Her Majesty the Queen now lives there more than at her other palaces, and those parts of the Castle are not open to view. Because of various royal activities and schedules it is very much worth while checking the online list of room closures. Our visits were usually 2 to 3 hours unless we were visiting the Chapel. Be aware that they get most tour buses in the morning right after opening.

If the 79 in your name reflects when you were born, then you've been alive as long as we have been married, so you may have more energy than us.

I would be unlikely to try to combine these in one day.

“I would be unlikely to try to combine these in one day.”

I 100% agree with Nigel. Give yourselves time to marvel at what you are seeing whether it’s regarding Henry VIII’s kitchens, lol or a building started in the 11th century or a place that has planted specimens older than the oldest building in Idaho.

If your time is short start a To-Do list for next time.

OP - you live in a wonderful area of Washington (we visit annually).
Short answer is "no" and Nigel's post says it all. Please take a deeper online dive into researching each destination to define your priorities. Also, check each destinations website to determine the activities available on the days you are considering attending. Nigel mentioned his membership in several of these groups and we found signing up and paying a small fee brought a wealth of information.

Thanks for the great advice. You have talked me out of trying to do two of these in a single day. I am trying to decide whether to do Windsor or Hampton Court on the Sunday we have available. The chapel at Windsor is closed to visitors on Sunday (except for worship) so maybe that tilts me towards Hampton Court which is also a little closer to London. Either way it’s all good!

Someone had great advice. Do some research on both and see which one has more of what you want to see. I have been to both, WIndsor twice because it has much more of what I was interested in seeing. You may feel Hampton has more of what you are looking for. We never considered Kew Gardens because that does not interest us that much. Honestly you can't go wrong after all you are in England!!!