Finished it last night. I'd call it a 60% success. The length is fine. The sleeves, as I suspected, are a bit too long. I don't know yet if they're too-long enough to be annoying; I'll have to wear it for real and find out. It needs more full-bust adjustment. I think this clinches it: Adult women cannot wear patterns that don't have bust shaping (darts, gathers, whatever). If I made a bigger size it would be huge around the neck, but it pulls a little across the bust and into the shoulders/fronts of upper arms.
I'll probably wear it awhile and see if we get along, but I'm going to start messing with other patterns for prairie dresses after this.