I'm taking a visiting aunt and uncle to an art exhibit at 70th and Park Tuesday afternoon, and wanted to find a nearby spot for lunch afterwards. They are in their 70s, and I was hoping not to have to walk far, preferably within 5 blocks. They have an early dinner reservation at Jean Georges, so lunch really doesn't need to be too fancy or a big production. But I'd like something fairly nice. I'm not familiar with this neighborhood - any thoughts?