We need a to scale floor plan showing where the toilet and vanity plumbing are now. Pics of the space are also a really good idea. I am assuming this is a powder room too. FYI in a PR vanity size can be ute small since there is no huge need for storage. Some idea of your style is also helpful

Thanks Patricia. Here's a pic I took from the comode. It should give an idea of the small space I'm dealing with.

In such a narrow space I would opt for another built-in that spans wall to wall. Even if you chose a 24" wide vanity that would only leave a few inches on each side. There isn't much you could do with that sliver on each side and it would be hard to keep clean. On option would be to install a vanity top on a metal frame but that wouldn't give you quite as much storage as what you have now.

I would do a vanity that fits in that space and what is all the stuff on the wall in the reflection? In tiny spaces wall clutter should be gone and if you ant to have a bit of fun do wall paper and no beadboard in such a tiny space.