i'm with others - book a nice hotel room using Cash & Points or all points. Just let your Grandmother know that some of the "internet folks" taught you how to do it "right!" I definitely would not want to have to go back and forth to New Jersey during the day; seems like that's adding a level of complexity that doesn't need to be there. Also, make sure you check out Senior Rates as your Grandma would qualify for those as well.
I'm all about making memories with my loved ones; much more fun and appreciated than "stuff"; both for you and her! Have a great time!