[Ecky]

How many miles?

I wouldn't worry about the battery, honestly. It'll go someday, but replaced by Honda in 2014 you might have another 6-8 years of solid use out of it. If it were a few years older, it would be a few years sooner. There really are no good alternatives, they're expensive and the ones that exist today are of lousy quality. When the time comes you can pony up for a new one with Chinese cells, bypass and run without it, or try your hand at something custom with another chemistry.

For what it's worth I've been driving without a battery for the last 3-4 months and it's "fine".