Every knight needs his steed and mine was gonna be a mule. I needed a bike that could really go the distance, as there was only two places to stop in the whole 500 miles. Both were truck stops; Coldfoot Camp and Yukon River Camp. There would be be no towns to get any needed parts or groceries. Basically this was logistically more of a backpacking trip than a typical cycling trip. Normally in cycle touring one passes through some sort of town once or more times a day, all the while on paved roads. You just buy what you need for the day, keeping the weight down. I was planning on 8-10 days for this trip. I had even read of someone taking 14 days to do it. Imagine backpacking with two weeks of food on your back, plus the weight of a bike and tools!
My strategy was to take six days food initially and ship the other six days' worth to Coldfoot Camp, located halfway. This would greatly reduce the total weight, although even with that measure it still meant a much heavier bike than normal. Six days food gave me a reserve in case of bad weather. Gee, this whole trip was "bad weather" for normal cyclists!
I chose a new type a bike, called a gravel bike. These are the hot new thing in the bike industry. Apparently every one must dream of cycling the road less traveled (and less paved). It is a spin off of the cyclocross bike; with a stronger fork, wider tires, and frame eyelets for rack and fenders. I got a deal on a Fuji Tread just before I left home. Completely untried by me, it was shipped North, and here I got my first ride on it. It has an all aluminum frame and carbon fiber fork. Not the heavy steel touring frame one normally chooses for a road like this. In fact most people cycle this road on a mountain bike, with even wider tires and a very strong frame. But being a contrarian, I shed nearly 10 lbs of the weight by choosing this type of bike.
I upgraded the gearing as much as I could (limitations with drop bars index shifters and mtn bike derailleur interface) to get a semi low gear for the many hills and mountains I would face. Unfortunately that would not be low enough I'd find out, as I'd have to walk of several steep grades in the mud.
The waterproof handlebar bag and rear panniers proved to be god-sent in the rain and snow. Simple inner roll down tops, like kayak dry bags, kept my gear dry.
Lastly, I moved my 15 year old mountain bike saddle onto this bike. Although it has minimal padding, I never had a sore butt. A good fit beats more padding everyday. Most folks think a cushioned seat is more comfortable, but it only increases friction and chaffing. A proper fit support the bone contacts points, not the soft flesh of the crotch. Look at the Tour de France riders and how thin their saddles are. My saddle is only a $30 one, but it fits me perfectly.
I never weighed my bike and gear, not having access to a scale in Prudhoe Bay. But it didn't matter, I only took what I needed, even throwing out my titanium fork to save weight! The weight was what it was, and I was going anyway! It probably good not to focus on a number and instead stay psyched to pedal across the Arctic :)