If I don't want to stay at the victoria hotel in Sapa, I gather I can't take the Victoria Train.
What is the next best train? Is there a train with a WC in the cabin?
Thanks.

See seat61.com/Vietnam.htm#Hanoi - Lao Cai

What you need to be concerned about is not what train you are on but what car. The Victoria has 2 or 3 cars and there are several other "soft sleeper" cars that go by various names. Ours was the Fanxifan Express car. The WC's are at either end of the of the cars, not in the cabins. There are 4 or 5 cabins per car with two or four berths each. If you want privacy, you can reserve an entire cabin for yourself (or yourselves). We were told that the Fanxifan Express car was one of the newer ones. Our cabin was not luxurious but it was very clean. The train can be jerky and noisy, so you won't get much rest if you are a light sleeper. The cabins near the ends are supposedly the noisiest. Be sure to specify smoking or non-smoking.

Try King Express or Livitrans for you reference, contact [email protected], she will help you more with many useful informations. I booked the King Express train with her and felt satisfied with their services.

I've taken King Ex and Livitrans several times - rather similar, but get Livitrans if you can. I hear the newest one is the Green train. All of these private carriages do get old and shabby, so it's good to get one of the newer ones. The quality is similar to Thai first class trains. Bring a snack as there's little to eat on the train. Remember that there's very little room in the compartments - you want to leave the bulk of your luggage at your Hanoi hotel or you will be very sorry and your compartment mates will not be happy campers! No one dresses in Sapa. The travel agent I use insists on taking me to the station (remember it's the rear one, Ga B, not the main station/Ga) since there's this stupid procedure where a special ticket is attached to your ticket coupon and tourists are usually confused by this. I use Diep at http://www.adventureindochina.com - a really honest, great and funny guy!