I'm travelling to the UK for the first time w/ my teenage daughters (15 and 13) end of July. We plan to spend about 5 days in London (itinerary loosely defined at this time), but would like to spend another 2-3 days at a different destination. I realize we can do day trips from London, and may plan to do a couple of these while based on London itself by train. I plan to either rent a car or take a train from London to get to our destination for the 2-3 day portion of our trip. But was wondering which of these locations, Oxford or Isle of Wight, would be more entertaining for me and my kids. We plan to hit many of the museums while in London. I fear they will be museum'd out, and won't want to to do many more of these toward the end of our trip. They're adventurous kids, don't mind a good walk, enjoy lots of different foods, love to shop (typical teenagers). Thanks for your suggestions!
If you Google "Isle of Wight activities" or "Isle of Wight things to do" you'll get a sense of the atmosphere and appeal of the place.
As for Oxford, I think you're right that most attractions are in the art-architecture-historical culture category.
It depends what your daughters are interested in, but 2-3 days exploring Salisbury & Old Sarum, Stonehenge, Avebury, and Bath might be fun. There is a fair amount of walking at Stonehenge / Woodhenge / Durrington Walls for those who want to get outdoors. More so near Avebury. See https://www.nationaltrust.org.uk/avebury/features/walking-in-the-avebury-landscape
Isle of Wight definitely, there's so much to do and fairly ignored by most non-British tourists. It's best to look at the Isle of Wight links provided to get a sense of what it has to offer.
If they are big Harry Potter fans, they might enjoy a specialized tour in Oxford to see locations used in the films.
Isle of Wight without a doubt. A relaxed vibe and easy distances between places. More of a contrast to London than Oxford would be.
Oxford can be done easily by train from London.
Isle of Wight would be a complete change from London and will let you see something of the countryside too.
Don't miss the ruined Carisbrooke Castle and go and meet the donkeys...
Go to Alum Bay with its multicoloured cliffs and sands. Get the Chair lift down the cliffs with views of the Needles.
Visit the Needles and walk round the penisinsula to find the two old batteries there.
Visit Osbourne house, much loved home of Queen Victoria.
do either of them have aspirations to study at Cambridge or Oxford; would they benefit from seeing Oxbridge in action? Pretty cool buildings and great atmosphere...
There is also Dorset area that is really fun and doesn’t involve getting on a ferry. Durdles Door has a wonderful beach to relax on. Walk there from Lulworth Cove, just arrive early to get a parking spot.
Perhaps the fun of going on a ferry is part of the holiday experience?
Durdle Door also gets horrendously busy in the summer...
If you spend two nights in Bath, there used to be a Mad Max tour of Cotswolds and Avebury that included Harry Potter's parents' "house". My college daughter and I really enjoyed that tour-at Avebury, you can get next to the stones,unlike Stonehenge. I think Durham is a more enjoyable college town for young adults than Oxford-there is a walking trail along the river and the cathedral has a Harry Potter sight.