I agree that, while S. Lucia station is about as far as you can get from P. San Marco in Venice, it's not a bad neighborhood and the distance is only relatively far. Historical Venice is not all that large to start with.

As to the 40 steps vs. vaporetto for luggage debate--I never found it to be a big deal either way. Pretty much personal preference. It's not as if it's something you have to deal with several times a day. It's similar to the big suitcase on trains debate--if I had to lift a big suitcase on a train every hour, that would be an issue for me, but to do it once or twice every 3 or 4 days is no big deal.

Now if someone had a temporary or permanent disability of some sort or was quite feeble, it could be a different story.

If you can't get your luggage onto a boat or over a bridge, you are packing too much; your suitcase is either too heavy, too big, or both

About Venice,
do most of the bridges have that many steps? How do I find out which hotels have such steps?

4 of are going to be dragging the luggage along. 80-100 steps sound very daunting.