I think a bathroom is a good place to start until you are sure: 1. the kitten knows exactly what the litter box is for and used it several time, and 2. the kitten has gotten a checkup at the vet, including a fecal for parasites. If the kitten has accidents, ear mites, or a parasite, it is much easier to clean and disinfect a bathroom than a bedroom. If the kitten is confident, is good with the litterbox, and checks out with the vet ok, it really should only be a couple days in the bathroom safe room.
In my view, a safe room doesn't need to be interesting. They need a litter box, food, water, a couple of toys, and the excitement of spending time with you, their new human. The saferoom should also be a time where the kitten gets used to you and you handling the kitten. Look in the ears, check teeth, touch claws, pet, play, etc. Knowing what is normal for your kitten is really important to taking care of it well. I see a lot of people letting a kitten loose and then not being able to tell when it is feeling bad, injured, or simply taking a long nap.
Good luck with your baby! They are so fun and grow so quickly!