Hi JS,
I found that everything so heavily depends on the weather!
I left Southern California Mid August and was in Fairbanks by the 31st. Ultimately I made it to Deadhorse and back to SoCal in a total count of 28 days. I'd recommend taking more time if you can. I was riding about 400-500mi per day and was in a new location every night. It is definitely doable but with more time it probably would of been an epic trip. I didn't leave myself much time to explore or take a day off. I also didn't get a chance to do the Top of the World Highway and have some fun in Dawson. I heard both were well worth doing.
By the time I made it to Fairbanks most of the local guys were advising against doing the Dalton so late in the season. Winter starts promptly on September 1st and this year was no different. Atigun Pass and the North Slope is always going to have risky weather year round but the later you go the more severe the conditions. Labor Day weekend saw multiple snow storms hit the Brooks Range and it really took a toll on my ride north of Coldfoot. By the time I made it to Deadhorse I was pretty shell shocked. I stayed two days at DeadHorse Camp to wait out some snowy weather but ultimately decided to haul my bike out with Carlyle Trucking. Even they ended up breaking down on the Dalton, haha. All civilian tours had stopped for the season so I had to fly back to Fairbanks via the local airport.
The Dalton is pretty tame from Livingston to Coldfoot. It is not technically difficult and the road itself was in pretty good shape. It's north of Coldfoot and more specifically, north of Atigun Pass that the conditions were noticeably different. If it would have been dry it would have been easy as the road isn't super challenging in terms of terrain. But the sub 40 deg temps, snow, rain, mud, and the wind (that was the worst part) really took its toll. Especially with the trucks bearing down on you and throwing mud across your facemask. After the 3rd spraying your pretty just pushing mud around with one hand and trying to stear the bike with the other. You do this for 200 miles through a really slippery muck about a couple inches deep. But like I said, if you go earlier in the season everything is a little less severe. And that makes a big difference.
So I'd recommend...
Go with a friend
Go earlier in the season as opposed to September
Leave time to do the Top Of The World Highway
A good windshield to get behind when those trucks come(i took min off in Calgary after it was causing a high speed death wobble)
Top Notch Rain gear (I bought a Helly Hansen slick suit in Canada that saved my a$$)
Heated Grips (cold hands on the Dalton will leave you helpless in a flat tire situation)
And stopping by this guy this guys shop in Fairbanks for tires before you hit the Dalton (Dan Armstrong - He was a huge help and very knowledgeable, and I found him on this site).
Unless you are sold on going to Deadhorse, I'd recommend only going as far as Lake Galbreath just north of the pass. I get it that Deadhorse is the "end of the road" but I really felt like a liability to the truckers north of that area.
In the event of an issue Carlyle Trucking was a big help.
The road itself isnt bad, but its the weather that can really get you. So reducing the weathers impact by going earlier in the season is probably the best advice I can give. This is all jsut dependent upon my 1 experience in the area though. Others may have a different tale to tell