Hi I am planning on walking the northern road in November..Starting in Egilsstaðir and walking west to Akureyri to Reykjavik. I will be self sufficient and have good equipment. I think this route is about 650km and I am planning on 30-35 a day..Is 3 weeks a bit ambitious? Can anyone tell me what the road conditions and weather is likely to be and any other bits of helpful advice would be appreciated.
Thanks in advance, Walkerman

Uh ehh, don't know where to start, why do you want to do this ? :) Maybe I'm narrow minded but all I can think of is darkness, short days, snow, bad weather and being alone in a desert.

snow
Rain also. Frequently arriving near horizontally. Snow does not persist for long near the coast at any time in the winter. To the extent that the road gets snowed on, it will be quickly cleared. But clearly there can from time to time be patches of ice/snow on it.
I wouldn't want to walk along the road even in the summer. Walking along the road in poor visibility conditions, especially the busier bit of the road from Akureyri to Reykjavik, seems like a dangerous idea. Although much of the road does have a narrow rough edge to it, where the road marker posts are stuck, though as it often slopes away from the road it may be easier to walk on if you had one leg longer than the other.
I am reminded of some Italian walker/cyclists who visited Iceland one Feb a few years ago. They had bicycles equipped with trailers that could be converted to sleds. They pulled these sleds over the interior of the country, including over the top of Vatnajokull, and then cycled when they got back to the road. Discovered by the police camping out in a blizzard by the southern ring road, they had some hard persuading that they absolutely did not require rescuing.
It isn't actually going to be especially scenic. The most scenic bit of the ring road is going the other way from Egilsstaðir, about as far as Hvolsvollur. But things are rarely particularly attractive under low cloud.
This is isolation. There is nothing for the majority of the road. And it certainly is not the most beautiful part of the ring road. You'd be better off heading in the other direction toward Hofn than toward Akureyri.
I think the biggest challenge would be ... boring time because much of the time you won't see much around. Or what you see around would be boring very often :-)
And the weather in November might be really nasty and neither winter nor autumn. Roads might be extremely slippery - so you'll need something to stay on very thin layer of fine ice.
So why not taking bus from one place to another and walk there - like AROUND Myvatn and around another interesting places?
Also think that south option might be more interesting (and challenging).

I hope this is a joke.
In November, there's roughly 8 hours of sunlight, and 16 hours of darkness, so you won't be able to see anything, and you'll likely be hit by any car driving by (or worse, cause an accident, as a motorist swerves to miss you) .
Why should he be hit by car in November? Are you judging from you driving habits? :-)
In fact his chances would be way much better at dark time (if he wears reflective stuff) than during day.
And 30-35 km per day is exactly the time he will cover when light is "on". The rest of the time would be spent to learn local life or maybe reading :)))))

Thank you all for your very welcome advice..
I think you nailed it Ruslendingur in your last reply! I agree I detected 'road rage tendency' from Cliffy by the use of the words ' worse still..... '
Some people don't seem to realize that properly equipped and responsible pedestrians (as well as cyclists) have equal rights on the road....
Surely it would be a worse case scenario that an irresponsible motorist crashed into an innocent pedestrian?
Remember we should never drive at a speed in which we cant stop safely at,and should always be capable of adjusting our speed for the prevalent road conditions.
Take care and thanks again, time to move on :)
Walkerman.