Parts of the north have such a rich and magnificent industrial heritage, you will expect to find buildings, history and culture that match that.
Other parts of the north were bypassed and remain hollow, neglected and uninspiring (Darwen, Blackburn, Nelson, Accrington, areas) and that's reflected in house prices and lack of employment.
Manchester is similar to London. It has it's neglected and trendy districts. It's pretty cosmopolitan, you won't feel like a 'southerner' there. It's not cheap. The villages around like Delph and Uppermill are great. Amazing scenery and a friendly community, yet still in very close commute to Manchester.
Ihave a preference for the other side of the Pennines though. Particularly West Yorkshire. I lived in Todmorden which seemed to be full of ex southerners and obviously Hebden Bridge which seems to have entirely ousted the native population in favour of ex Islingtonites. But they're the little prettified and artie-fartie towns. Maybe not your thing.
If you're concerned about your chikdren settling in, don't throw them in at the deep end, try finding an area which is already popular with southern migrants.
You will find it a culture shock. People are collectively different overall. I dont care if that sounds prejudiced. That's my personal experience of it. There's no etiquette and faffing about or playing mind games. If someone doesn't like you you'll know about it.
And yes, it does rain more up there. Fact. It's surprising how quickly you get used to it though.
Depending where you live, you'll never see a full sunset again. The sun falls behind the high moors by early evening in some places, so it gets gloomy quicker. The moors can be stunning in summer, colourful with yellow gorse and purple heather, but in winter they look black and foreboding.
But there's some jawdropping days out to be had up north, far superior to the over manicured south landscape.
It will make you feel far more grounded, earthy and insightful living up there. Even a little bit invincible 
. And I guarantee you won't look at your fellow Southerners in the same way again after a few years. It was actually one of the worst personal times in my life living up there, and I hated being pulled away from my beloved Westcountry town to move there, but the scenery and the culture and forthrightness and honesty of people in general has made me fond of the place and I'm grateful for the experience.
Look at it as a bloody great adventure but pick your new town carefully. Iwould really recommend Leeds or Manchester nice suburbs if you can afford it to start with, then do plenty of sightseeing and discover the places you might actually want to settle in long term that way.
And expect curry sauce on your chippy