Kris,
Items for over wintering in cooler zones are temp, lighting, water, possible pruning. I will address each in turn.
1. Temperature. How cold do you suspect the temps will get? If your plant is 3 foot plus, I suspect it is at least 2 years or more in age. It should have a "woody" trunk and main branches. If this is the case, It can handle the more extremes in temp. I have heard of people wintering hibiscus r-s in the garage by using a fire retardant sheet and Christmas lights inside. This gives a few degrees of added warmth to the leaves at night. Depending on the depth of the bottom roots, you may want to place it on a board, blanket, or cardboard. When the plant reaches to "cold barrier" it's leaves will droop dramatically. The best comparison I can give is it looks like it needs water.
2. Lighting. Do you have any natural lighting coming into any windows? If not, you will need to provide supplemental light of some sort. The plant only requires a few hours at most of natural light, but experience has shown that using indoor lighting requires 8-10 hours at the least. I use a combination of natural, florescent, and standard. Blooms are reduced significantly, but my goal is sustaining the winter. Reduced lighting will cause "leggy" stem growth and larger leaves. I will cover this in the pruning piece.
3. Water. If you plan for your plant to go into dormancy for the winter, reduce the watering significantly. Dormant r-s need very little water. Wait until the plant is about bone dry before adding water. Mine are inside, and I water about once every 10 days for 8-10 in pots and every 14-20 days for larger. I do have a small humidifier I use in the room, so I may extend the time by a day or more. The idea is to prevent excessive moisture and especially root rot and fungus.
4. Pruning. This is a special science much like a bonsai tree. It is ok to prune a plant before you bring it in. Remember to leave small node areas of small leaves to grow into new shoots, and a healthy dose of large leaves in areas to compensate for the reduced lighting. Remember that the plant will create lengthy new growth and the huge broad leaves are helping with the lack of light. These can all be taken care of in spring with a good pruning when outside again.
5. P.S. Notes. Fertilizer should be used sparingly and in low doses. There are good organics that have low counts of the essential elements. I would look for ones with additional content. Calcium, Iron, etc...
Hope this helps,
Ed