Keep in mind that the available codes are not usually posted so far in advance. The prevailing wisdom seems to be to go ahead and book the room you want at regular prices, then watch for codes as travel time approaches. If you find a code, you can call WDW and ask for the appropriate price adjustment.
I found codes for my March trip around Christmastime and last Spring got codes for June/July. You can check Mousesavers for past codes to get an idea what the discounts have been like. There is a section called "past disounts" with a calendar that lets you "speculate." I have gotten Riverside for $109, Coronado Springs for $114 and Wilderness Lodge for $139.
Hope this helps...