We had a discussion about older motor homes last week and the one point that came out clear was to pick a rig that had high quality when built. Beavers certainly fill that requirement. 1984 was before the SMC (Safari Motor Coach) purchased so Beaver was still building coaches in Oregon.
SMC bought Beaver and Monaco bought the whole mess in 2003 or so. You should have no issues getting parts because most of the components (fridge, stove, engine etc) are still being made. Body parts (front/back cap etc) can be had from a salvage yard like Colaws, but the older the coach the less likely it will be to find what you are looking for.
Another point from last weeks discussion was it helps if you can do most of the work yourself. And there will be work to do. Older coaches are a labor of love. The good side is, in a park full of "paper bag buses", yours will stand out.
Here's a link to everything you'll need to know about Beavers.
Click