Need some ideas for a very small bathroom in a 100+ yr old farmhouse

How about a shelf over the doorway? It's out of the way and usually can hold quite a few.

https://www.hometalk.com/diy/bathroom/organizers/wire-hexagon-shaped-shelf-26027398

I used a wine rack that goes on the wall I roll the towels up and place them in the spaces

It looks great they stay dry and ready for use .

Hooks on the back of the door. wooden 'art' boxes (4 sided box) with not back or front, hang on wall, roll towels and stack. Complete top shelf/surface for a plant or piece of artwork for extra color/contrast.

Think "up" as there is usually lots of room around the top of the room. You can even continue over the bathroom mirror and all along any wall except where the tub is located.

You can even use old dresser drawers as boxes hung up high into which you can put things.

I would look for wire baskets so you can see what is in them...one for shampoos and soaps, one for toilet paper, one for rolled towels, etc.

Try looking for baskets at your dollar stores. I know you can find plastic bins at Dollar Tree for $1. I bought some for my kitchen. They are rectangle and red! Labels could be added. I love mine!

We solved same problem in same aged house when my husband built small storage units for either side of the sink. We each have our own and they have drawers. Mine holds towels and his cleaning supplies and wash cloths. Maybe you don't have room to have something like this or necessary tools to construct. Another easy solution is to run narrow shelves around the bathroom, or as many walls as makes this feasible

Hanging baskets - Yes. Just what I was thinking if you want to keep the farmhouse look.

Hi, here are a few ideas for you:

roll towels on wine rack- this one is from Bed Bath & Beyond). Or you could craft your own). This could be mounted to the back of the door or on a wall. Another (found online)

I redid my clients 110 yo bathroom for storage. We added a shelf over the door for rolled towels, a second medicine cabinet, a tall covered toilet paper holder next to the toilet., a plastic storage rolling container with drawers between tub and sink. https://www.walmart.com/search/?query=rolling%20storage%20cart%20with%20drawers&typeahead=rolling%20storage

https://www.walmart.com/search/?query=toilet%20paper%20holder&typeahead=toilet%20paper

or you can do a door storage ... https://www.walmart.com/ip/Over-the-Door-Storage-15-Pocket-and-Vanity-Organizer-Beige-SET-of-2/373518286

https://www.pinterest.com/search/pins/?q=how%20to%20put%20a%20shelf%20over%20the%20door%20for%20towels&rs=typed&term_meta[]=how%20to%20put%20a%20shelf%20over%20the%20door%20for%20towels%7Ctyped

https://www.walmart.com/ip/GoodGram-Fabric-Shower-Curtain-Liner-With-Mesh-Pockets-White/127942324

https://www.walmart.com/ip/5-Tier-Plastic-White-Bathroom-Bathtub-Shower-Caddy-Holder-Corner-Rack-Shelf-Organizer/416929732

https://www.houzz.com/product/43479627-neal-wall-cabinet-with-2-doors-and-1-shelf-transitional-bathroom-cabinets-and-shelves

Most people forget about the space above their door. You can buy two shelf brackets at any Lowes or Home depot in metal (around the gardening section) or in wood (in the area where table legs are sold) and add a simple piece of wood on the bracket to make a shelf. Then you can not only store towels, but small baskets with other items that are needed, but you want out of site to guests. I have jars of cotton balls, q-tips, makeup, and such in a spice rack in the small space on the wall behind my door too, with a hand towel hung from the bottom.

I put a book case behind the door to keep towels in