Some x-pens come with floors that you can purchase seperately. Another option is using a bunny safe wood (ex. pine, cedar-untreated of course) and covering with lino. Or you can buy rugs (industrial rubber backed rugs are great because if they do pee on it, it won’t go through them). I find heading to a flooring/home reno store and just looking around is really inspirational too. And take a peek at the ‘cool habitats’ listed on BB here to get some great ideas as well!

https://binkybunny.com/BUNNYINFO/CoolHabitats/tabid/71/Default.aspx

I bought a rug that is under my x-pen. You can add houses and toys, things to climb/dig in.

I’m currently using a combination of newspaper and carpet squares with Rowan. He’s still leaving little accidents on the floor once in a while since he’s very young so I feel your same need to protect the floor. The carpet squares are very easy to clean and newspaper is replaceable so I find this method very easy to maintain.

for the floors in gizmo’s house we bought small carpet tiles (which i then fastened to the floor)
For the ground floor we bought lino for it, but we used an industrial rubber matting instead in the end due to the slippery nature of the lino

Gizmo’s “Run” was the dining room – we protected all the cables etc and i fashioned a “rabbit gate” in the doorway
She was litter trained so we just put a few small rugs down in strategic areas for her (cos she had her favourite spots and malted all the time) but other than that we let use the carpet in the room – she never tried to dig though, and never pee’d outside her toilet box

You may be able to pick up a decent offcut of carpet to use – or a decent sized rug, the lino we bought was an “offcut” that was almost the size of our dining room for about £20

We have an 8×10 rug cut to fit under our double xpen (pen is 4×8 feet). This lays right over our existing berber carpet and we’ve never had an issue with it. Our buns are littertrained so we don’t use any kind of plastic or linoleum, at least not right now. It cost about $60 at our local bulk store (Costco, BJ’s, Sam’s Club…) Whatever you use, you’ll want to make sure it’s easily cleanable. Twice a week, we just move the pen off the rug, vacuum the rug thoroughly (we pick up a TON of fur…) and then move the pen back into position. I prefer to not have to get on my hands and knees to scrub things, so this method works the best for me. Make sure the outer edges are outside of the pen.

I have a vinyl table cloth that you can buy at Bed, Bath, & Beyond or a similar store. It has felting underneith to protect my hardwood floors and is water proof in case my bun has an accident (though he never has). It is possible to chew where the folds are (I haven’t been able to get them to lay perfectly flat) but I haven’t had a problem with chewing, mainly because Otto can’t get to the edges which are the more tempting part to chew. I’m fairly sure he would chew/dig any kind of rug or carpet, so I’m staying away from those for now. The table cloth was about $15-20.

ETA: I also like the table cloth because it provides more traction than lino. Otto is ok with slippery floors, but much prefers something with traction. The vinyl kind of has a texture, which gives him a pretty good grip.

im not sure if this was suggested but you could use cardboard. its easy to clean up poo messes(pee not so much) and the bunnies can have fun ripping it. its cheap and works well. thats what i use. to make it welcoming i’d say put all their supplies like hidey house(make sure if they sit on top the can’t jump out of the pen) food/water, hay rack etc. provide lots of toys. if i was a bunny this would look pretty welcoming to me! you could add a slice or two of apple for a treat when they get in the new environment. when they have a familiar and yummy food i think that it would help them feel more comfortable.