As much light as possible, even if dormant. As you can see, they still grow. It also depends on temps they are in - cooler it is, less water they should get. Many ppl with those conditions do not water whole winter long.

It depends on the size of the pot too, if they look shrivelled I'd water them more often. Any leggy growth can be trimmed back in the spring when they go back out.

I have heard of cacti boxed up and put in the garage. Being checked on once or more during the winter.

What Rob said - my first cactus books (all European-based growing guides) mentioned them overwintering, wrapped in newspaper then put into a box, in a near-freezing basement / cellar / garage. If you cut them off from light, make sure they're kept dry, and around 0 C / 32 F, they can be stored like many other cold-tender things, like dahlias and the like. But, if you can, one of your goals might be to have a cold-hardy cactus and succulent garden (a lot would grow where you are), which of course never needs to be put away.