Hi carback ~
I'd like to second what Denise has said. I too have a Bike Friday touring bike (Pocket Crusoe) with 20" wheels. I had the bike built with gearing down to 17", I believe it is (30-42-53 chainrings, 11-32T Shimano XT cog), and this enabled me to ride loaded in the Adirondacks last fall. I'm not a strong climber and was still slower than my husband, and he carried more weight, but the point is, I made it up those climbs! I am 5'2", and with the 20" wheels I have absolutely no toe overlap, and the bike handles great. We carried extra tubes and one extra tire, but neither of us got so much as one flat in 9 days of riding approximately 63 miles per day, so we got lucky.
I have just posted on another thread here that I don't understand why so many women seem to be hung up on 700c-wheeled bikes at any cost. At 4'11", I have a hard time imagining that any 700c-wheeled bike is going to fit you optimally. Not that you can't ride it, but it's not the best choice. At your height, like mine, chances are a bike with 650c wheels (or smaller, like a Bike Friday, or a bike with two different wheel sizes, like a Terry) is going to fit and handle a lot better. Sure, the tubes and tires are a little harder to find, but so long as you plan in advance, there are many choices out there. Bike Friday offers a huge selection of 406 wheelsets and tires for my little-wheeled bike.
The nice thing about Bike Fridays is that they fold for easy transport on a plane (in the hard-case suitcase that goes as regular luggage), train, or even in your car, where they don't look like a bike (nice for security). That can be nice for getting to the start of a tour. I'm not trying to sell you on a Bike Friday in particular, but just wanted to point out an option you might not have considered. They are all built custom for your size, so you'd be guaranteed to get a touring bike that fits and has PLENTY of standover, with the one lower top tube. My husband loves his too! You can see pictures of us touring with ours last fall here, if you're interested:
Emily and Barry's NY State Bike Tour
I definitely think you're on the right track trying to achieve lower gearing on your touring bike, but do keep your mind open to other options than a 700c-wheeled bike. At 4'11", I have a strong feeling that you will be much more comfortable on a smaller-wheeled bike and be able to easily get the gearing you need for loaded touring in the mountains.
Good luck!
Emily
Emily
2011 Jamis Dakar XC "Toto" - Selle Italia Ldy Gel Flow
2007 Trek Pilot 5.0 WSD "Gloria" - Selle Italia Diva Gel Flow
2004 Bike Friday Petite Pocket Crusoe - Selle Italia Diva Gel Flow