Stop between London and Oxfrd

I would look at Marlow if you want to break up the trip. Very nice town on the Thames, has some nice shops. We had a nice pub lunch there several years ago- I believe it was the Two Brewers pub.

A town we enjoyed on our recent trip was Amersham. It’s 30 minutes from Heathrow. I can’t speak to the shopping, but it had a number of restaurants. We spent a night there.

Cliveden if the weather is good. National Trust has a cafe.

Marlow and Cookham are other possibilities. Both have many wonderful pubs.

And Marlow has a Murder Club.

Apologies. Refering to the Marlow Mysyery Club series that was recently on my PBS station here in the Land of La.

most of the places mentioned are not on the M40. Not too far off but not immediately near. Nice though.

The truth is that you'll spend as much driving time on the detours as you would on the trip without detours - once you are over the Chilterns you are almost there.

Beaconsfield and High Wycombe are on the way. Marlow and Cliveden are off the A404(M) and the A404.

Yes, Nigel is correct - I completely missed the point about a town along the M40...mea culpa....

However, I would not choose High Wycombe (even though Harriet Vane lunched "comfortably" there on her way to Oxford in Dorothy Sayer's Gaudy Night). Possibly Beaconsfield and the model village/railway.

Are there any National Trust properties off the M40 that would be suitable?

Are there any National Trust properties off the M40 that would be suitable?

Hughenden, which was the country house of Benjamin Disraeli. Situated 1½ miles north of High Wycombe so not far from M40.

Hughenden Manor involves going through High Wycombe and out the other side to get to it from the M40. Marlow is an easier journey and almost certainly quicker although parking can be a problem There are quite a few nice pubs and restaurants as well as some different shops. If it is a nice day, there is also a pleasant walk along the river.

The only other place near the M40 that comes to mind is Beaconsfield which has a quirky model village which depicts a sort of 1940s England and the Old Town has several nice pubs. The M40 junction is near the Old Town (parking can be difficult here too) but the model village (easy parking in the church - it's signposted) is in the 'New Town' about 3/4 mile away. Beaconsfield isn't far from Heathrow though and certainly not halfway to Oxford.

You don't say where you are staying in Oxford but parking in the City Centre is expensive and often hard to find (you may notice a pattern in my comments on parking) unless your hotel provides it and there is a recently-introduced set of 'Traffic Filter Control Points' (see map below) which you need a permit to pass through without being fined.

https://www.reddit.com/r/oxford/comments/1vt02q0/i_made_a_map_to_help_explain_oxfords_traffic/

Thank you everyone for your replies. We were originally going to stop at Cliveden but the house is not open for touring at the time we would be coming through. As nothing jumps out as a clear winner we will go straight to Oxford. I am sure there are many shops for my sister there. Any favorites?
I too am always concerned about parking and driving in towns (Florence and ZLT's started that phobia). We are staying at St. Margaret's Hotel which has parking. It's close to a bus stop, about a mile from the "downtown", so we will use the local bus while in Oxford and our car for the day we go to Bleheim and Woodstock.
Thank you also to the forum as I've gathered a lot of good Oxford planning from past posts. So far it's been a fun and challenging trip to plan as there are so many options. We will be in Great Britain 38 days.

Years ago we stayed at a B&B on Banbury Rd. on the far side of Summertown from where you're staying. The bus into Oxford runs quite frequently - we did not feel isolated by staying away from the town center.

In Oxford, probably the best places for small stores are the covered market in the city centre off the High St and Little Clarendon St which runs between Woodstock Rd and Walton St (about 5 - 10 mins walk from the market.)

My favourite pub in Oxford is the Turf Tavern best approached down a tiny alley off New College Lane. "Quirky" doesn't really get close. It's also supposed to be where Bill Clinton didn't inhale!

If you have a nice day, it's worth visiting the Trout inn at Wolvercote. It's very pretty with the fish swimming just below the bridge but last time I was there the food was very expensive and unimpressive. Nice place for a drink on a sunny afternoon though and there is parking.

There's a lot to do in Oxford and a search of this forum should pick up a number of postings about what to see - in particular, the tours of the Bodleian Library are very good but do get booked up. My only negative is the cost of entry to Christ Church college which is very high as a result of the Harry Potter connection. Quite a few of the colleges are free to enter.

One last thing - if you want to go into a particular college which says it is closed to visitors, it may be worth inventing a niece or nephew who is really interested in attending the college and who asked you to have a look round for her/him. The porters in the lodge (small office by the entrance) may or may not let you in but if they do refuse they will do so very politely.

Having both the places you want to drive to being to the north of Oxford it was a good plan to stay in a hotel in the northern zone. You can drive straight up the Banbury Road from your hotel.

Arriving by car depends on the time. This map description although unofficial is the easiest one I am aware of that makes the zones caused by the traffic filters understandable for those unfamiliar with Oxford geography.

If arriving between 3pm to 6pm Monday to Saturday (or 7am-9am) you need to exit the ring road from the north, coloured on blue on this map. If you enter from the east (brown) you will have to pass through a traffic filter in operation on the Marston Ferry Road and incur a penalty. Outside of these times you may use these routes.