Walker Office: 4288 3 Mile Rd NW Walker, MI 49534 Hours: Mon to Fri from 9am - 5pm. ... Grandville Office: 3050 Ivanrest SW Grandville, MI 49418 Hours: Mon to Fri from 8am – 4pm. For urgent medical issues only, our Walker office is also open on Saturday at 9am. We also have an after-hours support system (see below). After Hours Telephone Calls If you have an urgent medical situation that you...