This afternoon after work, Lisa removed the old drain hose and examined it more closely. It does not appear to be what's leaking. Moreover, the hose we bought yesterday is close, but not quite the right hose for our washer. In a pinch we might have been able to make it work, but given that it doesn't seem to be the part that needs replacing after all, we'll attempt to return it. (They did admit, after all, that they couldn't find the correct part, and we didn't actually install the part we bought.
Looking closely at the hot water feed hose, it looks like maybe that has developed a slight leak at the point where it feeds into the washer. That's a relatively easy part to replace. We're still trying to avoid having to spend hundreds of dollars on a new washing machine.
The trip to Reno yesterday wasn't a total waste (even if dining out was a bust). While waiting for the people at the appliance-parts store to find the part we requested, Lisa found a flexible duct-cleaning brush (made in USA, even). It's nominally for cleaning pellet stoves, but she was able to use it to clean the ducts in the furnace of her travel trailer, which really needed it. I saw the brush fish out a whole warren of dust bunnies. Current Mood: optimistic