Most of us usually enjoy a change of pace when we're able to manage it physically and comprehend what is going on.
Your concern about whether or not your mother will be willing to return after a "real world outing" is a reasonable one; especially, if she's expressing anger to you about the placement.
Here you are trying to do a good thing for your parents and move them closer to you and one of them reacts with anger. This is one of the many challenges of caregiving. Yet, you don't say whether or not your mom is also memory impaired. If not, she may feel out of place in this community. Even though she copes while you are not with her, she may feel trapped by the decision to move. She likely misses her home.
Are you able to have her over for a night for a change of pace?
If she's cognizant, you could discuss with her your concerns—you'd love to take her out but fear her anger and resistance at returning. Maybe she may just need to vent. (How could you, her own flesh and blood, do this to her?) Let her vent and she may then be able to move on with accepting the situation.