Ok - where do I even begin?? Firstly, you can't imagine how happy it makes me to read this - I LOVE to see other families out on the road!! I can promise you that you will not regret it.
My boys are now nearly 12, and are doing just fine with the biking. We left Alaska when they were 10.5 and did fine then too - so your son should be just fine. That being said, you'll have to consider your child - one of our twins is perfectly capable of riding his own bike, while the other would never be able to concentrate long enough to do it safely. Depending on your kid, you may need to consider a tandem.
Be aware that you will encounter some people who feel that you are torturing your child. You will be (in their eyes, anyway) the worst parents on the face of the earth, and your child should (obviously) be taken away from you. But by far most of the people will support you more than you can even imagine. People will reach out to you in so many ways - giving you a bag of tomatoes, filling your panniers with oranges, offering you a hot meal and soft bed to sleep in, lending you their car so you can take side trips, etc... The list can go on and on and on.
I've written up a series of interviews with other cycling families - asking them some of the questions you probably have swimming around your brain right now. Hope these help you!
- spent a year cycling Europe and North Africa with four kids
- currently in Peru on two tandems with boys aged 11 and 13
- just took off with 9-year-old son for an open-ended tour
Rebekka, Flo, and Chan
- cycled from Vancouver to Tierra del Fuego. Left when son was a toddler.
I've also got quite a few other families listed in the blogroll of my blog at www.familyonbikes.org/blog
One thing you will have to be comfortable with is ignoring the US Department of State warnings - a lot of them are out there for political reasons. (I had the embassador to Ethiopia personally beg me not to leave Ethiopia because the warning was purely political and had nothing to do with our safety). Pay attention to the Candadian and British warnings - they seem to be much more accurate.
Please know that I support you completely and will do my best to answer any other questions you might have. Email me at firstname.lastname@example.org