Does your mansion contain any custom graphics? If so, you need to wait until Anthony (and hopefully other custom graphic users) find out how to make those mansions playable in the HD. If you want to participate in solving the custom graphics issue then you should perhaps start a thread in the
custom mansions art board.
If your mansion does not contain any cg, then you simply need to check whether it is playable from the beginning to the end in the HD format. Read
Vern's FAQ to find out how to convert it to a HD ready format and then play your old mansion from the beginning to the end.
The things to look for are:
1. Are there any ladder issues (if you have made any ladders using ladder tiles in an unorthodox way, like in some of Freddy's mansions).
2. Are there any levers that are not in level with Jack (if not he can't pull them).
3. Does Jack ever have to jump from a ghost platform in one room to another one in the next room? If so, they both need to be of the thick type since the thin ones are always off when Jack arrives in a new room.
There may be some more issues that I don't know of.