BigBlueToe

I'll speak to the knee thing. I have two road bikes, a Surly LHT and a Specialized Allez. I have triple chainrings on both of them. It's an obvious choice for the LHT, which I load up quite heavily on tours. Pushing that load up a steep mountain pass obviates the need for a low setup. It has a 24-tooth granny and a 34-tooth large cog in the rear. That has been sufficient to get me up all the hills I've encountered to date.

The triple chainring setup on the Allez doesn't go nearly as low - I think the granny is a 30, and the cassette is a 10-speed with narrow intervals. The big cog isn't all that big.

The only time I've had issues with my knees was when I rode another bike over the North Cascades Highway pulling a Bob trailer. It didn't have low enough gears so I had to grind out the miles in a too-high gear. My knees got so sore that I ended up aborting the trip (having Sherman and Wauconda Passes still to come.

Anyway, the lowest low on the Allez still involves some grunting going up hills. I'm not suffering as much as people with doubles (although maybe a compact double would give me as low a low? I have no experience) but it's not as easy as the setup on the LHT. On that I feel like I could climb almost anything with ease - maybe going ridiculously slowly, but that's okay.

So, to wrap this up (I can make a short story long, huh?) I suggest you look into a triple chainring, and maybe a 9-speed cassette, rather than 10-speed, for the simple reason that they seem to offer 9-speeds with a much wider range than 10-speeds.

Okay, others will undoubtedly suggest a compact double and, like I said, I have no experience with them.

The bottom line though is to make sure you have really low low to protect your knees. And then develop the habit of spinning - keeping a fast cadence - rather than grinding a higher gear.