Training a horse who hasn't been rode for two years.....?

Ive just started looking after my neighbours thoroughbred, who is an ex racehorse, standing at 16.1 hands! However, she hasn't been rode for two years and I'm hoping to bring her back to her former self. So what exercises should I do with her on the lunge rope and riding her to ease her back into being rode? Any tips or advice would be much appreciated! :-)