As mentioned, RD codes are for rentals only. They have not been used in many years; they date back to the recession, when Disney was looking for extra channels to rent out inventory. If I remember correctly, they were never particularly good deals either. Any exchange will be subject to the $190 nuisance fee.
At present, DVCMC only deposits 1BRs. The
overwhelming majority of them have been at SSR. Most times of year are deposited, but some periods are harder to get (October, early December, race weekends, etc.) You may have to be patient; deposits can come as early as seven months prior, but tend to be closer in. I confirmed my most recent exchange about 4.5 months prior to check-in.
DVCMC deposits to both RCI Points and RCI Weeks. Ongoing searches match only to Weeks; you have to book Points by searching yourself. If you are a resale-only Wyndham owner who has not enrolled in PlusPartners you will only see Weeks inventory. If you have a contract that was purchased from the developer (or enrolled in PP standalone back when that was possible) you can also see Points inventory.
Finally, if you have not already done so it is worth joining TUG (
https://tug2.net/). For $15/year, you have access to their Sightings board, where people actively post the DVC and other prime inventory they see. Well worth it.