Cairnryan to Alnwick with children, where to stop

[Serenitespring]

We’re traveling from the ferry at Cairnryan to stay in Alnwick Northumberland on Saturday 26 May, this Saturday coming.
I’ll be driving with kids 10/8 years.
I’m hoping for any advice as to where to stop to break up the journey, see thing/play areas/where to eat.
Google maps gives two routes, one up by Glasgow and over by Berwick and down, 4.5 hours
The other straight across Dumfries, Carlisle, Hexham 3.5 hours.
I’ve never been to any of these places.
I’ll need to break up the journey, so don’t mind stopping off, make the journey part of the holiday.
Any and all ideas welcome as to where we might stop to eat and play/visit sites.
Is there a website that helps you to plan journeys with restaurants/ kids day out ideas?
Have posted on Scotsnet too but hoping for lots of advice do here also

Hexham route - Stop at Gretna Gateway. Or there's a nice farm park (Walby?) on the A69. Loads of Roman sites along the A69. Hexham has a lovely park.

Hexham or Durham.

Depending on how tired you all are, I'd factor in maybe a short pitstop at Dumfries or Gretna, or keep driving a little bit longer to Carlisle to see the Castle. If you'll be driving on the A75 (which I presume is where your satnav will direct you first, unless you fancy driving on small unclassified roads...), be warned, that road goes on FOREVER. It's much, much longer than you think it is looking at the map and there's not much on it in terms of rest stops, ironically given that it's pretty much the only way to get to Cairnryan and Stranraer from east to west.

You wouldn't go that near Durham on that journey unless you have a VERY odd satnav indeed, it's quite a bit further south.

The A69 has lots of nice little stops along the way (Haltwhistle, Hexham, Corbridge) you could also come off on to the old Roman Road (B6318, normally quieter, locally sometimes called the Military Road) which follows the route of Hadrian's Wall, complete with Roman forts and stuff should you feel the need. Probably one of the straightest roads in Britain (those Romans knew how to build....!) Housesteads and Vindolanda, both on this road, are two of the biggest forts near Hexham, with Housesteads reckoned to be the better of the two by some tourist sites - have a look at https://www.dayoutwiththekids.co.uk/things-to-do/north-east/northumberland/hexham/sightseeing for a few ideas.

It's a stunningly lovely part of the world (in my opinion, having grown up down the road in Newcastle) and I dream of one day retiring there - you'll have a great time.

Gretna Gateway is a great pit stop - has toilets, play park, pizza express, Burger King, space to
stretch legs. We always stop there on the way to Cairnryan.

Thanks everyone. I posted on the amazingly helpful Scotsnet too and have gotten done great ideas.