We're having weekends away at the moment (DS is a young teenager).
We are doing Premier Inns (very clean at the moment) because a 5 star is wasted as we're out all day and it's a place to sleep!
But a couple of weekends ago we did Blenheim Palace. A weekend ago we did Beulieu motor museum (DS and DH are car nuts) and Monkey World. A couple of weekends time we're off to Longleat and Stonehenge.
We often do UK holidays in the school holidays. Last year we rented a wood cabin type lodge in Stratford Upon Avon and did all the Shakespeare sites, went to the brilliant Attic theatre (which isn't open yet as it is literally bench seats in an attic - but they are doing an outdoor tour of Wind in the Willows - worth seeing as they are hilarious).
Two years ago we did Cornwall - stayed at very lovely self catering near Bude. We walked into Bude (and as DS is a teenager his legs won't walk far - they seize up with a moan at about a mile) but even he enjoyed that. We went on pedal boats and went round one of the little museums, did the beach. Then went to Tintagel. We spent the day in Lynton/Lynmouth in Devon (worth going to the little museum there to learn about the Lynmouth flood in the 50s), we went to Agatha Christie's house in Devon. That's National Trust.
We go to Scotland regularly as DH is Scottish - Loch Ness is lovely, Aviemore gives you access to the Cairngorms (if the reindeer centre is open it's worth a visit as they take you on a short walk up the mountain and you feed the reindeer - our DS did the walk first time aged 6 and there was a lady on walking sticks in front of us who managed so it's not a hard walk). Lots of farms there that do sheepdog shows and you get to meet the dogs which is lovely.
The lake district was lovely about 3 years ago - we did Coniston and Windermere lake boat trips.
Northumberland four years ago took us to Holy Island - driving across the sands knowing that area would be under water later was a thrill for DS! We went to Vindolanda which is a roman fort excavation - fantastic museum with the Vindolanda letters (written on wood that has been preserved in the clay mud for 2000 years - one of them prove that women of the time could read and write which was thought unlikely until they were discovered). We also did Hadrian's wall. Then there's Alnwick Castle (where Harry Potter's quidditch matches were filmed - lovely castle too and the grounds are beautiful with a poisons garden - every plant is poisonous). And of course Bamburgh Castle with the beautiful beach nearby - Michael Fassbender's MacBeth was filmed on that beach and it is stunning. The castle itself is lovely and the people are so helpful.
We went to Belfast and did the Titanic exhibition then went to the 'dark hedges' (featured in Game of Thrones) and then to the Giants Causeway.
We went to York for the day on our way up to Northumberland - Jorvik
Viking Centre was great with a ride around a 'Viking' settlement (with all the smells...not so great ha ha!)
Easiest thing is to go on line, type in the type of thing you like to do and plan around that. I use Trip Adviser a lot for that as you can type in a destination, look up hotels, restaurants, things to do all in one place and research more from there. It gives you a good general overview so you can whittle down the list.
To be honest I love UK holidays. We live in a stunning country with a huge history. And our tourist places need the support now.
Just take a raincoat or brolley - there is nothing like being on Bamburgh beach in the rain. The sky is fantastic as the clouds roll in!