They sell tile "stickers" -- sorry, I have seen them in magazines but can't recall where to buy them -- maybe someone else knows -- but that may be your best solution for the 2nd bath. You can stick them right on top of the offending tiles.

Do you have a bath w/ shower curtain in the avocado bathroom, or a glass door? If you need a shower curtain, I'd suggest that you shop for one that has a tiny bit of your avocado color in it, along with some other nice colors, and pick a wall color from the curtain. If you want to de-emphasize the avocado, stay away from any pink colors or colors with pink undertones. The pinks/reds will only accentuate the green. You could really play with the avocado, though, and experiment with some colors that make it a fun/funky bathroom. We were stuck with a bathroom once that had horrible yellow fixtures -- toilet, sink, and shower stall. I'd never seen anything like it. We couldn't change it, so we painted the walls purple, hung up a large, bright print that had lots of purple, yellow, and other colors, and it was actually kind of a fun look. (This was a summer cottage, though, not my full-time house!)

My rental bathroom has an olive green bathtub, a white sink and toilet and three different patterns of peel and stick tile on the floor, two with more blue tones than anything else. And off-white walls.

After a very long time trying to merge the olive and blue, I ended up finding a shower curtain with a bit of the olive tone, several other shades of greens and some tan and brown. I bought towels to match the tan in the shower curtain and a bath rug that covers as much of the floor as possible while still allowing the door to open. I have chosen to ignore the floor as much as possible. I've brought more greens in with a picture or two on the walls and a few small accessories, so now the room reads as "room with several shades of green and tan," as opposed to "room with really ugly olive green bathtub that goes with nothing else."

The problem with the olive and blue bathroom things that I found was that I just didn't *like* them, although they would have solved my decorating dilemma. In the end, I chose to go with something I liked, that didn't completely coordinate what was existing in the room, but that I could live with long-term.

I've read of people using double-stick tape to put a row or border of tiles up on a wall--don't know if that would work in your second bathroom. Or maybe gluing a wide grosgrain ribbon over the border? (Using glue that you can remove when you leave.)

Could you post a pix of the border, close-up enough that we could see the color and design?

Thanks for the excellent suggestions -- after much soul-searching and hard thought, I've decided not to rent this house because 1. I am re-doing the entire thing in my mind and 2. It's a rental and I don't know how long I would stay......so that's that for this place and it's issues.....I'm sure I'll have more questions for the group once I do find that "perfect long term rental" that I am looking for!

Good for you!
Nothing more frustrating than a rental that is all wrong, and having to put effort into the things that aren't yours, instead of the things that are, like your own furnishings, and your time and your friends and family and life.