Travel Britain with a family of 6 - most economical lodging?

With a group as large as yours, and for a 3 week stay, you might be better off looking into rental homes and holiday cottages in central locations from which you could strike out on day trips into the surrounding area. They're usually much cheaper that hotels or B&B's. Some require a 7 night stay but we've found that even if we only stay 4 or 5 nights we're usually saving money over other types of accommodation. They're also handy for being able to eat-in occasionally rather than having to dine out every day - saves a lot of money doing it that way too.
Aside from the popular search engines like homeaway.com and booking.com, we've had good luck with these folks while touring in Ireland: https://www.sykescottages.co.uk/. They have lots of properties in England too, many of which are quite unique, ie thatched cottages, etc.

Where are you heading? Coastal areas and tourist areas such as the Lake District will be busy with families, as it’s school holiday time. August isn’t the time for economical accommodation. You will need to book ahead for many locations.

Bedrooms will have either one double bed or two single beds (twin room). Some places have family rooms, if your children are younger. You will be unlikely to find rooms with 2 double beds, as you get in the States.

Premier Inns offer reasonable value in many places.

You cannot sleep on floors, as this won’t be permitted by hotels and you are likely to be asked to leave if you are overcrowding the rooms.

Sykes Cottages have many cottages on their books, but many of the properties they offer are dated and basic and they are certainly low-end. English-country-cottages.co.uk have a nicer choice and there are many other agencies offering cottages. You will find that most cottage agencies will only rent for a week in peak season, but a cottage would be cost-effective.

For 6 people, you will need to rent a people carrier or a 7 seater car, (or 2 cars), but many of these have limited amounts of luggage space.

Look at Booking.com rather than Airbnb, as it offers better value.

I can't resist; sorry. Is this the plan you are basing your itinerary on?

3 days: London
•5 days, add: Bath
•7 days, add: York
•9 days, add: Edinburgh
•11 days, add: The Cotswolds and either Stratford or Blenheim Palace
•14 days, add: North Wales, Wells/Glastonbury, Avebury and/or Stonehenge
•17 days, add: Lake District, Hadrian's Wall, Durham
•21 days, add: Scottish Highlands, Liverpool, Ironbridge Gorge
•24 days, add: Choose two of the following — St. Andrews, Glasgow, Cambridge, South Wales

I am one of those who thinks Rick's itineraries are too fast for independent travelers. A car is an advantage some of the time, because you don't have to tie yourself to train or bus schedules, but moving a family of six around at a pace like that seems extremely challenging.

I'm also wondering what size vehicle you're planning to rent that will accommodate six people and their luggage, yet still be comfortable to drive on sometimes-narrow rural roads.

In terms of lodging, consider whether you will need or want air conditioning for part or all of your trip. Heat waves are not terribly common, but neither are they unheard of. Air conditioning is a rather rare thing in apartments; I'd guess the same situation prevails in holiday cottages, but it's not a subject I've researched. It's easier to find a/c in hotel rooms. Premier Inns often have it, and many Premier Inns have a two-person bed (not necessarily queen size!) and a single/twin bed made up as a sort of sofa but with a real mattress. One of those rooms could accommodate 3 people. The rate at PIs can be quite reasonable if you're booking well ahead of time, but do be careful to book the correct rate. One of the two options is totally non-refundable.

Great advice so far, especially about housing!!

We love quirky, funky, unique, off the beaten path places to stay, so don't be afraid to suggest some. Could care less about amenities other than hot water and a bed (laundry every now and then). I hate air conditioning, so I'll be happy.
The itinerary is tight, but we've all traveled together before on tight schedules. BUT, that's kinda the reason I didn't want to lock in housing for the entire trip.

I think I will rethink things a bit and maybe consider a more hub/satellite approach to this trip so that renting a house is an option (though I fear it will eat up time).

I will have no trouble driving whatever size rig they give me on any size road. Plenty of experience with that. While that is not one of my concerns, I understand how it is worth mentioning by some. We are traveling super light on luggage.

Thanks again and keep the suggestions coming.

Some B&Bs have more than one bed per room. You just need to check before booking.

For example if you want to see the Cotswolds, stay at Chipping Campden and the Volunteer Inn.

Don't wing it in the Summer. Also, the great places book up even in the shoulder seasons.

Personally, I would do Bath and Stonehenge as day trips from London, skip Blenheim Palace and see Windsor instead. If you were planning to go to Oxford, you could do a day trip from London to Cambridge instead. Even York is possible as a day trip from London. Of course, you will spend a lot on train travel if you do day trips from London and London is a very expensive place to stay. You could do Hadrian's wall on a bus tour from Edinburgh and do Durham as a day trip from York. You might want to compare the cost of the car and petrol and parking to train fares. Driving on narrow roads on the other side of the road can be quite challenging. I've been on tours to the Cotswolds twice and would not prioritize them. With kids, you should consider Cardiff, Wales and a visit to the nearby St. Fagan's outdoor museum. If your kids are Harry Potter fans, you need to get tickets to the studios now as they sell out months in advance.

Just out of curiosity, what have you rented transport wise? I only ask because you don’t want a van in the Uk but would need a people carrier type car for 6 plus luggage large or small. A van is for moving goods about. Not people.

cala (above) idea about staying in London & taking day trips out - presumably by train as you would not want a car in London - means that you would be paying for accommodation in one of the most expensive cities in the world. You would also have to be paying for all those people on the trains.

You might be better off renting a cottage(s) at some central hub location - which could be out in the countryside. Try and google cottage holiday rental & the areas that you are interested in visiting.

Also check out this chain:>https://www.travelodge.co.uk

If you want unusual, check out National Trust rentals and Landmark Trust, castles, towers, thatch, follies, light houses, forts, its brilliant! Alot of the properties date back to the medieval period, so you can totally immerse your self in history😀. Definately no AC, but thick, thick walls are very common. These do require a min of 3 days stay i think.
And i too vote for slowing down, it doesnt sound like a relaxing trip to me. But then maybe that is just another example of tbe European/American differences?

Good advice regarding the Landmark Trust properties - had forgotten about them.
I also agree about getting out of London and into the countryside as soon as you can. Trying to do day trips from the most expensive city in Britain is probably not your most cost-effective option.
Booking self-catering cottages and vacation homes will be a much more pleasant alternative for you and your family I think. Lots more room to stretch out and relax at the end of a busy day exploring.
We've only used Sykes cottages in Ireland and so can't comment on the quality of their properties in England, but we've been quite happy with the places we've rented from them in the past - most were absolutely charming. My wife especially liked some of the thatched cottages we booked in the west of Ireland - would guess that they offer similar quality accommodations in England as well.

The Landmark Trust have some interesting historical properties, but they are top-end price wise and many are smaller houses.

In peak season, many places will only rent for 7 nights.

I agree with acravens comments. I wouldn’t follow RS’s itineraries they are too fast, they don’t give you time to stop at different villages you drive through if you want to stop. There are hundreds of beautiful, quaint villages/towns that aren’t included in his itineraries. I would wing it. I would look at a map and decide on a route you want to take from one place to another, then research interesting places to visit. There are hundreds of B&Bs that only rely on their sign only, because of the cost to advise. There are B&Bs that has rooms where three people can sleep in one room. A few years ago we drove around England in June and July, it’s was myself, husband and four sixteen year olds. We didn’t book B&Bs ahead, when we decided it was getting close to the time we wanted to stop for the day we would watch for B&B signs, never had a problem finding a room for the four of us. You can also go to a village/town tourist information center and they can book a room for you. The advantages of not having every single night booked is you can spend as little or as much time at places, and not having to worry about getting to a certain place by a certain time. Also, it will take longer to drive to places then you think.

Have you used AirB&B before? Last summer we spent 5 weeks in Denmark and stayed in 8 different AirB&Bs. With a car you should be able to stay 3 or 4 nights in each place and then take day trips to see the are sights so no need to constantly pack and unpack. You can stay outside of cities and find more funky and interesting and cheaper places. You can get a kitchen and save a ton of money. I highly recommend looking into this approach. Make sure you look for Superhost places.