They're right- cats are heavily stressed by changes, and they have to kind of take their OWN time adjusting (in other words, you both probably want her to be affectionate and accept some loving and feeding and caring, but it's got to be HER IDEA, basically). A bathroom works perfectly for initial getting-to-know, that's what we do with trapped ferals (it's also easier on the clean-up in the event that litter-box training doesn't proceed as quickly as desired). We just sit with them and talk gently to them and hold and pet them when they allow it, and gradually they accept things-- they seem to WANT to accept us, but the change and their caution prevents them from jumping right in......but it always works! Be there for her and let her take her time......
there's nothing on earth so rewarding.....