You don't go to England for the weather. Even in the summer.

England with teens is a great idea.
Harry Potter tours
Stonehenge
Warwick Castle which has lots of activities for young people including a dungeon
Stratford (Shakespeare plays)
London (Buckingham Palace, Parliament, outdoor markets, Hyde Park, and the Tower of London)
Oxford and Cambridge and punting on the rivers
You might even have time for a day trip over to the WWII Normandy beaches in France.

For some reason, I am leaning towards Paris (make my husband "endure" 3 nights as I have not been there in a long time)....and then something rural. But rural with ruins, castles? towns. I just went to London for work last year...... OK I am driving myself crazy with confusion. Second choice Scotland? Although April?

You all have great ideas. My kids are in high school and they aren't really into Harry Potter. They like ruins, animals, sitting in cafes, hiking and some cathedrals and museums... just not all day.

If you've just been to England then Paris would be fine too. I think your teens would enjoy Paris especially lit up at night and it certainly has lots of art galleries (the Louvre, D'Orsay, my favorite the modern art Georges Pompidou), Nortre Dame, a river trip down the Seine, Eiffel Tower, lots of great gardens, cafes, etc. Then take some side trips to various castles within a few hours by transit. What's not to like?

I don't think it matters where you go particularly - having time with your family is what counts. Plus you and DH sound like experienced travelers I think it will depend on the options and activities your twins would like.

(First a disclaimer: I only mentioned Harry Potter in my post about the NE of England upthread because Alnwick Castle, one of the premier sights of Northumberland, was used for numerous Hogwarts scenes in the movies. Even for non-Potterites, it's still a stunning place.)

But okay, Paris plus something: How about a couple of days in Paris, followed by a quick train ride (or quicker flight) to the south of France, followed by a few days exploring parts of Provence and Languedoc? Take the TGV to Avignon, get a car, and visit the stunning Roman ruins in Nimes, the Pont du Gard, Avignon itself... then visit the Camargue - historic Aigues-Mortes, flamingos and wild horses in the marshlands, maybe the castle town of Carcassone... picturesque villages, hikes, ruined castles (and some that aren't) lots of intriguing history...

Google these places.

that looks like a pretty solid idea. Ordered guide books and will google

Yes Avignon only about 3 hours by high-speed train from Paris and nice weather and as Gadryloo says everything you want. Pont du Gard old Roman aqueduct is stunning - last I knew can still walk on top. And Avignon has Palace of Popes - huge old castle in town center. Stay in a smaller town with car and sample rural French life too. St-Remy-de-Provence is a favorite with many here - right neat Avignon. Google Les Baux-de-Provence - right next to it - take a drive to the Camargue and ride ponies into outback to see the famous wild horses and flamingos.

hire a barge, most places let you take out a barge without qualification along canals, there are loads of canals, lots of walking along tow-paths, eating in restaurants and watching the world go by while chatting to the locals

and many barges have bikes on them so some can cycle between stops or after barge has docked for night. Not cheap however.

If you go to Aigues-Mortes and the Camargue pack mozzie protection, even in April the blighters will eat you alive.

Have a look at le boat.com and see if they have anything that appeals if you want to go boating. They offer boats all over the place. Friesland (my new home province) is perfect for boating and will still be pretty quiet when you want to visit.

thank you. I will and I think my kids DO want to go there.... will definitely pack something with DEET

Paris, then Dordogne or
Paris, then San Sebastián, Spain.

We did spring break in London and Paris with grandkids, first week of April plus a few days. Snowed in London, very cold and raw in Paris. They loved London the most because of Harry Potter.
Southern Spain, Andalucia would be great.Or Portugal. What foreign language are they studying in school?

You might consider flying into Barcelona and then explore the area there north into France to give you a taste of both places. And I think the number of days you have will work well there The beach areas there are nice all the way up to Narbonne and Beziers and flying in ann out of Barcelona usually gives you lots of options. We love basing either in Barcelona itself or just south or north, Castelldefels is nice just south of Barcelona and Roses is a great beach town further east/north closer to France that we love. And Both Spain and France have easy and high quality health care.

Also just in case you aren't aware of it, dialing "112" anywhere in the EU is the is emergency services number, equivalent to the US 911 number. All operators will speak their own language, English and French. https://ec.europa.eu/digital-single-market/en/112

And in France there is also a service called SOS Médecins and most medium and large cities will have walk in clinics that are very inexpensive. And if you are ever really stuck and need medical help but don't really need the emergency service, in France for sure go talk to a pharmacist-they are very highly trained and they are also likely to know the local clinics and doctors in a village for instance. In my experience, all village tourist offices in France also have a list of doctors and clinics.

Really helpful. My main concerns are if he were to get sick.... it would wreak havoc with his blood sugar so that is good to know. Or if his bag with his insulin got stolen.... Thank you

I really like Gardyloo's Edinbugh-to-York itinerary. If your kids like ruins, they'll love Hadrian's Wall. And Durham is one of my favorite places. Edinburgh and York aren't half bad, either. I've been to the UK at all times of the year, and was never disappointed. I would think twice about a camping trip or a beach holiday there, at any time of the year.

There was an English graduate student some years ago in our department at Princeton, who once was complaining about the rain. I said, "Come on, you're from England!" She replied, "The rain here is rainier than in England." I understand her meaning.

You should look into southern Spain Andalucía - Granada, Malaga, Rhodes, Seville. For that time of the year it would be better in my opinion than Scotland, France etc weather wise...good combination of culture/castles outdoor activity. No real hiking but I'm not sure you want to be in the mountains at that time of the year.