Average Speeds over Long Distances

[Annoying Twit]

Now I'm planning to do 300km in one day. Oxford return might do this if I find a suitably twisty route.
rate.

Here's the route to Leicester I used to use when my daughter lived in a village north of Oxford
https://ridewithgps.com/trips/4392318
Just about 100km one way and not particularly hilly, and no significant traffic, so it could make an alternative to your Lincoln rides. How you'd. Stretch it to 300k? Maybe via Northampton?

Looking at your route, you use A roads and go through the centre of towns. (Banbury in this case.) That makes things shorter.

I generally go through tiny villages, and can make the route longer by going through more of them so that my route is more twisty. I have a route that I used from Oxford to Leicester, and it was 136km. The extra distance came from small scale twistiness from village to village, rather than going on a large diversion, e.g. to Northampton.

Though, the route I actually used was even more twisty, as the route I have stored goes through Daventry, while in reality I went through Norton to the east of Daventry. route to Oxford on Google Maps

Not going through towns is actually problematic for longer trips as there are no large supermarkets in tiny villages. That makes it harder to buy more food on the way.

I did make use of the Fosse Way, which you use to go to Oxford, on my route back from Gloucester via Stratford-Upon-Avon.

[meic]

Leaving the main roads tends to not only being longer but also being slower. They tend to be hillier (around here) and have more stops, turns and other things to impede progress.

On the Brevet Cymru mentioned by Phil Chadwick earlier, progress is greatly enhanced by a long stretch on the A40 in the dead hours of the Sunday Morning.

[Annoying Twit]

Leaving the main roads tends to not only being longer but also being slower. They tend to be hillier (around here) and have more stops, turns and other things to impede progress.

Definitely. But, some of the main roads around here are downright scary. On the way to Lincoln I cross the A52 and A17, and go under the A46. EDIT: And over the A1. All of those are too scary, for me, to ride on. When I went to Newark-on-Trent return I made a wrong turn on the way back and ended up on the A52 for a few km. I most definitely did not enjoy the experience.

I'd rather be slow than squished. But, perhaps I'm being too conservative. It also adds time to the journey as I use a printed paper route and have to stop to read it between occasionally and often, depending on how well I know the area.

When I went to Rutland Water as a night ride, there was no traffic at all that I could see or hear. I think that taking the A-roads at night might be good, but I don't know which roads have limited traffic at what hours.

[meic]

I agree and I tend to ride on the lanes instead of the main A roads, this is reflected in my average speeds.

[mjr]

I'd rather be slow than squished. But, perhaps I'm being too conservative. It also adds time to the journey as I use a printed paper route and have to stop to read it between occasionally and often, depending on how well I know the area.

You'd probably not get squished, but I don't ride the main roads either. I don't fancy listening to motorists' noisy engines more than I must, though.

Writing an abbreviated audax-style route card and following Sustrans routes as much as possible can help with routes. I'm mostly lazy and use the phone sat nav voice prompts now, but that comes unstuck when we have a difference of opinion about what's a turn and what's straight on - and I can't hear it reliably in London... but it's lots quicker not looking at everything on maximum zoom and sometimes on street view or the Bing equivalent.

[Annoying Twit]

I try and base my directions on those I received on the Audax I did. However, I'm not as good as they are. On the Audax I noted that if I just applied common sense in terms of which fork or part of a road is 'straight', then I'd find that the instructions worked. I tend to add in directions more than the Audax did. My routes are also more twisty. But, otherwise I try and do the same thing.

EDIT: Having looked closer at the Audax instructions you link to, they are more structured than the ones I received for the Audax I did, and even more structured than the ones I write myself.

I attach a screen grab of the first part of my Lincoln instructions. Note that the first two lines cover the first 12km or thereabouts, as I know the route too well to bother writing it down. Note that "DON'T GO TO SAXELBY" is due to previous off-route excursion

[Phil_Chadwick]

On the Brevet Cymru mentioned by Phil Chadwick earlier, progress is greatly enhanced by a long stretch on the A40 in the dead hours of the Sunday Morning.

Saturday night for me

Can be hairy if you don't bypass Brecon.

[PH]

I try and base my directions on those I received on the Audax I did.

You might want to look at Alfreton CTCs Audax routes. Some of them you could incorporate into your longer rides, or even if not they're good examples of clear route instructions and not over complicated. I have no problem following them, which isn't always the case with some others.
Maybe you might consider doings some, they're reasonably easy to get to from Leicester give me a shout if you want some company, I'm in Derby.
http://www.alfretonctc.netii.net/audax.htm

[Annoying Twit]

I try and base my directions on those I received on the Audax I did.

You might want to look at Alfreton CTCs Audax routes. Some of them you could incorporate into your longer rides, or even if not they're good examples of clear route instructions and not over complicated. I have no problem following them, which isn't always the case with some others.
Maybe you might consider doings some, they're reasonably easy to get to from Leicester give me a shout if you want some company, I'm in Derby.
http://www.alfretonctc.netii.net/audax.htm

I'll look into the audaxes that are listed. The next Leicester one is in February, so I hope to find something suitable before then. But, it has to fit into our family plans. Thanks for the offer of company. I'll PM you should I be going on any of those.