Volunteer Management and Community Engagement

When you have a big neighborworks organization and you require various types of volunteers that can build capacity in your organization, but your volunteers are to work at various locations with very diverse set of resources and hours, what do you think is the best way to manage volunteers? Currently we have coordinators for each site who can work with the volunteers, but would it be beneficial or even efficient to have a Volunteer Coordinator that oversees all volunteers and or interns at all sites? Could we utilize a volunteer to help manage and support are volunteer program. Furthermore, is their strategies you find useful to get volunteers who are looking to volunteer, but are constantly constrained by factors like transporation. I am exploring new ideas and trying to come up with a strategic plan as I am an AmeriCorps VISTA focuscing on Volunteer Developement