Our activity coordinators included:

Safety - Need an overall safety plan

Hospitality and Food Events

Planning and Recording:

Recreation & Special Events:

Additional:

Organizational Suggestions
Expect about 20 - 25 Marines
Hosts
You need to find enough volunteers who will host Marines in their homes.  The hosts need to dedicate the entire period to their guests, providing transportation and accompanying them to their various events.  Hosts provide breakfasts.  We had lunches donated by local restaurants, but you could have hosts manage that instead.

Medical Group
You need to team with a medical group who will offer physical therapists with experience caring for handicapped and who will provide on-site first responder care.  We teamed with the Roger C Peace Rehabilitation Hospital that has adaptive equipment for handicapped water-skiing. It may also be necessary to provide adaptive equipment for other activities such as golf.  Roger C Peace staff are willing to advise you on what you need.

How it worked for us at Keowee Key
Law Enforcement
You also need to have some law enforcement/security people on hand to manage safety - you don't want any incidents.  We had the coast guard auxilary, our security and fire people on hand, and local law enforcement available to support the "shock and awe" arrival.  During the motorcade, all intersections were blocked by law enforcement.

We recommend you keep them in your community unless you are escorting them to an event.  Do not let them out on their own.  Remember that they are just returning from combat and don't need the irritation of some vocal opponent of our involvement in Iraq and Afghanistan.
Food
Biggest expense is food.  You can get a lot of it catered and donated but need to plan for it.  We received monetary donations and then paid for their meals, but you may want to develop other options.  Second biggest expense is beer and wine.  You will not want to use donated funds for that purpose because you can run into difficulties with sponsors.  However, local liquor distributors will often donate beer and wine for appropriate events.
Additional Costs to Consider
Don't overlook cost of gas for boats, jet-skis etc.  We covered that with donations so that individuals who were hosting did not end up with a large bill.   
Event Planner
Considerations
Transportation To/From Base
It will be necessary to pay for a bus to transport them from Camp Lejeune or Pendleton and back.  MARSOC does not have funds to provide the transportation.  We are looking into a contract with a bus company near Camp Lejeune, but even so, it could cost upwards of $2500.
Media Relations
Media relations management is essential.  You need local pre-event coverage to make sure that communities along the route show up for the motorcade escort.  You also want the community to know about events that might affect them so that they are tolerant of any inconvenience.  You also need to carefully manage media access during the event.  While you want to encourage press coverage and assist the press in covering events, this is R&R for the Marines and you do not want the press in their face any more than you would want press coverage of your vacation.  You also do not want a warrior who is inexperienced in talking with the press to say something in a relaxed atmosphere that he may regret seeing in print.
Two co-chairs managed the event with other individuals taking responsibility for various activities and recruiting for their committees (recruits were typically friends and neighbors).

Over 150 people volunteered to participate.