Someone recommended a houseboat for our stay in early to mid October. Does anyone know if this would be cold/wet or pleasant?
You can go to wunderground.com, look up Amsterdam, then drill down to historical monthly weather stats for October of 2016, 2015, etc. One of the graphs shows hour-by-hour temperatures. Looking at several years' data should give you a decent feel for, the range of temperatires you can expect. As for wet, I think Amsterdam tends to be very damp, but I've not been there in October. The summary chart on Wikipedia suggests that you should expect rain almost every other day of the month, on average.
How do you plan to deal with laundry? I wonder whether you'd have a problem getting things dry. I'd want to find a bunch of reviews for that time of year for the specific boat I was interested in that addressed how well it was heated.
We were there mid-October last year in a houseboat. Don't recall being uncomfortable in any way.
We stayed in a Hostel Houseboat this summer. The MPS Holland. Very small and cramped, but cheap. We made do. Owners were friendly and helpful. Decent free breakfast with ham, cheese, bread, coffee, tea, jelly, pancakes, etc. Laundry was a 20 minute walk. We brought our own washing power so we knew how much to use. It is about a 20 minute or so walk from the Central Train/Bus station.