After a fabulous holiday last year at caseiro del mirador Jalon, recommended on here this year we're a tad skint. I'm thinking Wales? We have 3 yr old and it will be in school holidays. I don't know Wales at all, so totally ignorant
Clydey Cottages would be your friend. I don't think the philosophy would be that different to CdM. Best holiday ever with a toddler, and all designed with families in mind. It's in a lovely part of Wales and there are loads of toddler-friendly things to do nearby.
Pembrokeshire would be good, lots to do,great beaches if the weather is good.
Otherwise, staying in the cardiff area gives you a city, with no end of toddler things to do, museums, fantastic parks and events with the option to go out to the beaches at Barry. Or further afield. You can camp in cardiff city centre in a lovely campsite near the castle in a park.
We had a fantastic holiday in Snowdonia, North Wales. It was a small person paradise: beaches, castles, steam engines. You can also go pony trekking or biking.
We stayed in a self-catering place near Betws y Coed which has the railway museum. We used the car to get around and went to several castles of which Conwy was IMO the best. The beach at Fairbourne was a lovely surprise (thought it would be dire but lovely although no loos or cafés further up so take picnic and wee in the sea or dunes!) and it has the miniature railway.
Worst case scenario is that it pours with rain some of the time. But there's plenty that can be done even if it's chucking it down. I remember an excursion to Lechwedd Slate Caverns in order to avoid the downpour. I like staying very near a beach, because then it's easy to get out as soon as the downpour stops.
I very much like the coast between Harlech and Barmouth -possibly better for walking, scenery than touristy sight-seeing. But then some families are quite happy to set off in the car for the day. (It can take a while to get places as there are quite a few mountains in the way.)
We had our best family holiday there and we've done Mark Warner on the Greek Islands and all sorts of typical holidays like Cornwall.
Often you just need to go a little bit further up the coast (like at Fairbourne - the bit by the ferry is good) to get away from the touristy bits. It's definitely much less hyped than Cornwall so it's less touristy overall and much, much cheaper. The scenery is just beautiful.
One thing I wouldn't bother with again is going up Snowdon. It is v v expensive and actually quite boring after the first ten minutes or so. It was boiling hot when we went so being sticky and unpleasant just made things worse. We also couldn't see anything because it was rammed with people and the children got fed up.
The thing with a holiday like this is that you expect to be doing things all together. We did the trail around the waterfalls, got fishing nets and went crabbing, dug big holes built sand castles on the beach. We'd take a picnic out with us so we could be more flexible with timings and hungry toddler. The children would often drop off in the car so they would be up later in the evening so we planned that in. We watched DVDs, went for evening walks, played tag in the orchards, kicked a ball around, cooked dinner altogether... lots of lovely things we hardly ever get to do as a family because we're so busy working and the children are at school/nursery.
Would definitely recommend Pembrokeshire with young children. More beautiful beaches than you could possibly visit, and lots of other family friendly places to go eg Folly Farm, Manor Park wildlife etc. Lovely pretty small towns with plenty of facilities, eg Tenby and Saundersfoot, but lots of countryside and smaller villages too. Loads of options of self catering accommodation to suit all tastes and budgets. The two we have been to with dd were Lydstep caravan park and Bluestone. Both fab in different ways.