Would Appreciate Feedback On Tentative Plans

Arriving in London and immediately jumping on a bus tour (I assume you are talking about a hop on hop off tour?) can be a disaster if you didn't sleep much on the flight over. While it is best to be outside on arrival day, sitting on a gently swaying bus for an hour or more could become an expensive nap for your group (it happened to members of my family of seasoned travelers). Better to walk around and get your bearings, then take the tour the second day. Do you have 12 nights on the ground or 12 days? It makes a difference. Remember that if your flight is in the evening, it will be the next morning when you arrive. Make sure you aren't counting that in your 12 nights (or days).

You should really make some time for Glasgow. There are a number of things that would be great for kids the age of yours, and many of the museums are free - Kelvingrove and the Riverside Museum of Transportation are fantastic. You can also take the train to Balloch to catch a boat tour of Loch Lomond.

Day 1 - go for a walk, not a bus tour to get over your jet lag.

Your Man U game could be anytime between Friday night and Monday night - the exact timing will only be confirmed c 3 weeks out, depending on TV schedules, so be prepared.

Take the train to Manchester - the traffic from London can be hideous and stressful. The Cotswolds aren't really in the right direction anyway and London to Manchester is a 4 hour drive on a good day - probably more like 5 hours on a Friday. If you do drive to Manchester, go up the A1 not the M1 - usually fewer hold ups and take a look at Rutland Water - about half way and just as pretty as the Cotswolds, but without the tourist hoardes. The museum in Oakham is worth a quick visit - they have hundreds of horseshoes (which sounds dull but your children will enjoy), presented by kings and queens etc going back centuries. A unique place.

Manchester to York is easily reachable by train - stay in York rather than backtracking to Manchester. Alternatively, visit Chester from Manchester - a great cathedral. Blackpool is a rather tacky seaside town - consider a day trip to Alton Towers instead from Manchester or Thorpe Park from London.

Drop Inverness as it's too far for one night. Loch Ness is a tacky tourist trap and your kids are 10 years too old to be fooled by the hunt for Nessie. Spend this night as another night in Glasgow - visit the Trossochs from there and Loch Lomond - far nicer than Loch Ness.

You may get some ideas about things to do in Manchester and Glasgow from my trip report: https://community.ricksteves.com/travel-forum/trip-reports/uk-trip-report-glasgow-manchester-liverpool-in-september-2016

For your kids as well as you, definitely plan time at the Manchester Museum of Science and Industry, and make SURE you are there for one of the demonstrations, either of the engines http://msimanchester.org.uk/whats-on/show/engine-demonstration or the cotton-making machines http://msimanchester.org.uk/whats-on/show/manchester-mills-demonstration. Your children will definitely perk up when they hear the stories of people their ages working in the extremely dangerous conditions of the mills.

I agree with the suggestions above about Glasgow. I'll just reiterate that most of the attractions in Glasgow and Manchester are free, so it you or your kids are not having a good time, you can easily move on to something else. I also agree that Blackpool is far to go from Manchester; they may prefer some sights in Liverpool, particularly if they're Beatles fans. I didn't discuss it in my report, but almost all of the museum in all three cities make concerted efforts to interest children.

I think this trip might work better by train. You are covering long distances and you are staying in cities where a car is a nuisance (and expensive to park).

The only tricky part about using the train is that your Manchester dates are uncertain and you need to commit yourself to get the cheap train tickets. Perhaps you can set your dates and get the tickets and then have several options in mind for day trips.

Good luck with your planning

Jennifer offers sound advice. Use www.nationalrail.co.uk to fond train schedules. (Pre-book about 11 weeks in advance specific trains for the longer trips to get cheaper fares). If you are using a car to go from Manchester to Scotland, I would swap Blackpool for the Lake District. The Cotswolds are too far off your core routes.

Big thanks to everyone that has posted advice. Very helpful!

Dundee is much nearer to Edinburgh than to Glasgow. If you want to visit Dundee, it's not far from Glamis Castle (country home of Elizabeth the Queen Mother's family) or from St. Andrews. Stirling is also not too far. You could then take train or bus from Edinburgh to Glasgow.

There is both a Holiday Inn and a Holiday Inn Express right at Glasgow Airport, literally walking distance to the terminal. We've stayed at both. Preferred the Holiday Inn because the beds are a little more comfortable, but both are fine.

Thanks. I was planning on doing a day trip to St. Andrews from Edinburgh and was wondering if we could/should fit in some time in Dundee that day. My Grandmother was from Dundee and while I am not aware of any family I may have there, I was still thinking about a half day or so.

My wife and I have read and considered all of the posts. Thanks again for all who offered (very helpful) advice. Here is how we have tweaked the original plan that I laid out in the first post (we also have our plane tickets now, so that is set).
Arrive 9am Monday morning in London. Take the train to Manchester on Friday. Stay in Manchester 2 nights. Catch the game, spend time in Liverpool and Manchester. Train to York. One day in York. Train to Edinburgh. Instead of going to Inverness/Loch Ness, split remainder of trip (5 days/5 nights) between Edinburgh and Glasgow. We are flying out Saturday. We cut out Cotswolds (can always go later after the kids grow up and we want a slower trip). Cut out Blackpool (sounds a lot like the Jersey Shore which I don't go to a lot even though I live an hour away), and I think we are cutting out the rental car all together. Did some research, and I think we may go with a 8 day Brit Rail Pass. Everyone agree with no car, all train?

Agree with using the train. It will be the fastest way. You can use your time on the train to study a map or guidebook for your next destination, eat a sandwich, take a nap, or enjoy the scenery out the window. No car equals no getting lost, no yelling at the navigator, no accidents or damage to car by scraping bushes or walls on narrow roads, no getting stuck in traffic, stress level cut by about 90%. A big thumbs up to "all train".