Hi,

Boston ferns are humidity lovers, but they can adapt to being indoors in low homidity. They might look a little rough at first, but will come around if treated right.
A cooler room is better than a warmer one if you can provide it. The soil should be on the moist side (semi moist) at all times. Mine is in a 8" pot and gets watered well once a week, sometimes every ten days depending.
Bright indirect light or dapple light is best I think, strong direct sun can burn the leaves to a crisp, as well as letting the soil dry out completely. Over-watering will eventually cause yellowing and rot.
Mine gets fed lightly in the spring and summer and none in the winter.
Keep it away from any direct heat in the winter, such as fireplaces, heating vents, lamps, etc..
You will always have some brown tips on some of the fronds and some whole fronds turn brown now and then, just pull or snip them off, but the plant should still look nice and green everywhere else. If you can provide any additional humidity I'm sure it wouldn't complain.

The runners are not roots and do not indicate a need for repotting. Just keep the soil moist and it should be fine.

Pans of water will help increase the humidity close to the pans. However, your fern can adapt to low humidity if you keep the soil moist.

"Repot every year" is a rule of thumb that applies to plants growing in the ideal conditions of a greenhouse. It does not apply to most houseplants where conditions are far from optimal. Repot only when you are having a hard time keeping the soil moist.

The thread-like runners are called stolons. They are a reproductive mechanism. When the stolons come in contact with moist soil they produce new plantlets. In nature, they travel along the moist ground and help the plant to spread out. In a pot, the stolons will not find moist soil and eventually will wither. You can cut them off at any time without it damaging the plant.