Vic, those are honking looking rims and tires...wow, what size are they? Would sure be handy on those sort of roads, would float over most soft stuff I imagine?

as for walking, I guess its all opinions, I hate doing it, would rather bike even at a slow speed---but its a moot point if he is going to be using a 60-ish gear inch ss...as he shall be walking at some point. Ive gone down teh Oregan coast and it sure aint flat.

I might as well say this, but Im not sure a single speed is really a great idea, not for the Oregon coast.

If you have your heart set and decided on it, I second the suggestion of loading your bike as per the trip and seeing what is doable for you hills wise. You then will really have an idea of what is realistic with this idea. My knees hurt just thinking about what you are thinking of undertaking.

+2 on finding gearing that allows for an relaxed run of the mill cruising speed of 20kph or so at a nice cadence. I personally wouldnt go much higher than that as you will suffer the consequences with every uphill.

My average touring speed on many trips was always around 17kph over the day, with hills and such. With a triple crank.