Thanks for the reply!
Yes, from the videos that I've seen, and articles read, it seems the best idea would be to ferment in glass first, then transfer.
This is a new barrel, with a light toast. I've swelled it already, am ready to clean and sterilize. Some use a fifth of Jack to do this, which sounds right to me.
There's a cool video from Goose Island, showing them funneling fruit right into the barrel for the secondary ferment. For a large brewer like them, they probably transfer again for distribution, so carbonation is no issue. I did read a little on real ale this am, and was encouraged. If the English can still do it....
The other choice is just to brew something cheap, and work to get the barrel to pop a bit when I tap it, for a good show. Brew a cheap recipe, and then roll the barrel down a slope to the fest, then pop in the bung?