The Marathon weekend does get the hotels sold out but the parks are still fine as long as kids are back in school. This past year many districts didn't go back until the 8th so it was pretty crowded until then. In terms of booking the package we did room only and then switched to a package but this year I'm just waiting for packages to come out since you can't just switch a room only to a package anyway. In terms of discounts there is always something in January. The bigger issue is that they get booked up for marathon weekend so in order to get a discounted room you may need to be willing to be flexible on resorts. We couldn't get discounted rooms at PO-FQ so we switched up to AKL for not a huge price difference.
Yvonne