Well, today went better than expected! My son helped me install the fork and headset, and then he prodded me to get a bit more done. Thanks to the advice earlier in this thread, I was able to get the bearings installed, and not over-tightened. The handlebars spin free and do not bind anymore.
And, we wound up turning the Goose back into a roller today!
I should be done with it this week if the Postal Service can find the two parts we need to finish it.