How can I find matching cabinetry and hardware?

First......I would call the manufacturer of the RV. They may have one in stock.

Yes to a cabinet shop...however, a lot do not make their doors, they bring them in. Check around and see if you can find a local shop that makes doors. This will not be a standard cabinet (kitchen) door size so it will cost a bit more.

It doesn't look like hardware matching will be an issue. You will need to look and see how you are going to mount the doors. There are a variety of hinges.