Id leave the vanity blue and go with a light gray white on the walls hang so art work and change out the light fixture. DIY frame the mirror in white (lots of online videos pretty easy) maybe change the pulls to a long modern handle in gold or brass, and change the faucet and light to that as well. https://www.houzz.com/products/quorum-enclave-3-light-vanity-aged-brass-prvw-vr~89697288 https://www.houzz.com/products/cosmas-161-96bab-brushed-antique-brass-cabinet-hardware-euro-style-bar-pull-prvw-vr~127381366

@Sharon Perkins Really great result and such a difference for making the counter look perfect! Love the new mirror, repositioned medicine cabinet & wall color! Thanks for coming back to show us. And, your lovely son-in-law - is he good with the changes after seeing how good it looks?

If you don't change the tile I don't see the point in trying to change the wall color. What is there is a good match for the tile. The vanity top isn't great, but I don't think a white-white would be an improvement because the tile is a very warm color. The white toilet really stands out - not in a good way. You could always look at remnants in slab yards to see if there is something else you would like better for a vanity top. There may be something available in a big box store off the shelf that would work if the vanity is a standard size. I think the wood vanity works with the tile. Since this is the only bathroom I would just leave it alone as any change is going to be quite disruptive, and without changing the tile, not a big change.

Try bright colors. The navy rug isn't bad at all. Also test out turquoise and different greens. Wallpaper can be a good way to blend pleasing colors into a bathroom with blah tile, and you have so much tile that you can get pretty wild with wallpaper without it being overwhelming. If you decide on wallpaper you can repaint the vanity a crisp white or something from the paper. (Keep the groovy knobs.) The mirror fits the bathroom if you want to keep it "authentic" (which is probably the way to go when keeping tile like this). The light fixture not so much! (Nor the sink...but sinks are more of a hassle to replace than lights.) I'd look for something retro (keep it chrome) and simple sort of like this: https://www.lampsplus.com/products/george-kovacs-saber-20-inch-wide-chrome-bathroom-light__h7689.html How bad is the floor? It looks like it might just need regrouting, but I believe you if you say it needs to go. Trust Palimpsest on floor suggestions.