I moved my mom to assisted living in the early stages of alzheimers. My suggestion is to make the room familiar, but do not bring too much stuff. Clutter can be overwhelming and when adapting to a new place, having things clearly organized is going to be helpful. (We ended up getting a label maker and labeled all her drawers). She moved from a house she had been in 50 years, and she was an only child who inherited all her parents stuff. I had to get rid of generations of antiques, papers, etc. I did it quickly (maybe too quickly) but I kept a few pieces of art, which I brought to her new place, along with family pictures.
In our case, my mom moved about a year before diagnosis (by that point she was stage 3/4--I had thought early but really she was already mid stage).
We paid a lot to have the largest apartment (850 square feet), with a nice kitchen, and a nice table for eating, bookshelves, and a computer desk, etc.
She never cooked (not even toast!); went to meals all the time (which was probably for the best, given her decline); she stopped using a computer and pretty soon stopped reading most things, just the paper and some novels.
Then she had to move to memory care, and we had to get rid of the table, chairs, couch, rug, TV, bookshelves, kitchen stuff, computer, phone, etc. Much of which we had bought new since it was cheaper to buy new furniture than ship her old stuff across the country. If I could do it all over again, I would have furnished sparely, and been prepared for the fact that she wasn't going to need the fancy wardrobe, pots and pans, a coffee maker, etc.