Hi,
I wanted to confirm it is possible to display the Field_Service_Report__r(custom object), 
Notes and Attachments, OpenActivities and other related list on a VF page that is being accessed via guset user at saleforce site, in admin mode it works fine.

My VF Page
<apex:page action="{!CheckSession}"  controller="CaseDetailController" showHeader="true" cache="false" sidebar="true" tabStyle="Case">
    <chatter:feedwithfollowers entityId="{!objcase.Id}"/>
    <apex:form >
        <apex:pageblock mode="maindetail" title="Case Detail">
            <apex:outputpanel >
                <apex:pageblocksection title="Case Information" showheader="true" collapsible="true" columns="2">
                    <apex:outputfield value="{!objcase.CaseNumber}"/>
                    <apex:outputfield value="{!objcase.OwnerId}"/>
                    <apex:outputfield value="{!objcase.Origin}"/>
                    <apex:outputfield value="{!objcase.Priority}"/>
                    <apex:outputfield value="{!objcase.Status}"/>
                    <apex:outputfield value="{!objcase.Stage__c}"/>
                    <apex:outputfield value="{!objcase.Type}"/>
                    <apex:outputfield value="{!objcase.Reason}"/>
                    <apex:outputfield value="{!objcase.CreatedDate}"/>
                    <apex:outputfield value="{!objcase.ClosedDate}"/>
                    <apex:outputfield value="{!objcase.Site__c}"/>
                    <apex:outputfield value="{!objcase.AssetId}"/>
                    <apex:outputfield value="{!objcase.AccountId}"/>
                    <apex:outputfield value="{!objcase.ParentId}"/>
                    <apex:outputfield value="{!objcase.Is_Expenses_Claimed__c}"/>
                </apex:pageblocksection>
                <apex:pageblocksection title="Contact Detail" showheader="true" collapsible="true" columns="2">
                    <apex:outputfield value="{!objcase.ContactId}"/>
                    <apex:outputfield value="{!objcase.Contact.Phone}"/>
                    <apex:outputfield value="{!objcase.Contact.MobilePhone}"/>
                    <apex:outputfield value="{!objcase.Contact.Email}"/>
                    <apex:outputfield value="{!objcase.Contact.Fax}"/>
                </apex:pageblocksection>
                <apex:pageblocksection title="Description Information" showheader="true" collapsible="true" columns="1">
                    <apex:outputfield value="{!objcase.Subject}"/>
                    <apex:outputfield value="{!objcase.Description}"/>
                </apex:pageblocksection>
                <apex:pageblocksection title="Web Information" showheader="true" collapsible="true" columns="2">
                    <apex:outputfield value="{!objcase.SuppliedCompany}"/>
                    <apex:outputfield value="{!objcase.SuppliedEmail}"/>
                    <apex:outputfield value="{!objcase.SuppliedName}"/>
                    <apex:outputfield value="{!objcase.SuppliedPhone}"/>
                </apex:pageblocksection>
                <apex:pageblocksection title="I&C Detail" showheader="true" collapsible="true" columns="2">
                    <apex:outputfield value="{!objcase.P_O_Number_I_C__c}"/>
                    <apex:outputfield value="{!objcase.P_O_Date_I_C__c}"/>
                </apex:pageblocksection>
                <apex:pageblocksection title="Case Assignment" showheader="true" collapsible="true" columns="2">
                    <apex:outputfield value="{!objcase.Service_Center__c}"/>
                    <apex:outputfield value="{!objcase.Engineer_Vendor__c}"/>
                </apex:pageblocksection>
                <apex:pageblocksection title="System Information" showheader="true" collapsible="true" columns="2">
                        <apex:outputfield value="{!objcase.CreatedById}"/>
                        <apex:outputfield value="{!objcase.CreatedDate}" id="createddate" label="Created Date"/>
                        <apex:outputfield value="{!objcase.LastModifiedById}"/>
                        <apex:outputfield value="{!objcase.LastModifiedDate}"/>
                </apex:pageblocksection>
            </apex:outputpanel>
        </apex:pageblock>
</apex:form>
<apex:relatedList subject="{!$CurrentPage.parameters.Id}" list="Field_Service_Report__r"/>
<apex:relatedList subject="{!$CurrentPage.parameters.Id}" list="CombinedAttachments"/>
 <apex:relatedList subject="{!$CurrentPage.parameters.Id}" list="OpenActivities"/>
 <c:CaseComments CasesId="{!objcase.Id}"/>
 <c:CaseHistory CasesId="{!objcase.Id}"/>
 </apex:page>

My APEX Controller

public class CaseDetailController 
{
   public case objcase{get;set;}
   public CaseDetailController ()
   {    
       
   }
   public pageReference CheckSession()
   {
             objcase = new case();
             objcase = [SELECT AccountId,AssetId,BusinessHoursId,CaseNumber,ClosedDate,CommunityId,ContactId,Contact.Name,Contact.Phone,Contact.MobilePhone,Contact.Email,Contact.Fax,CreatedById,CreatedDate,Created_By__c,CreatorFullPhotoUrl,CreatorName,CreatorSmallPhotoUrl,Description,Engineer_Vendor__c,HasCommentsUnreadByOwner,HasSelfServiceComments,Id,Invoice_Date__c,Invoice_Number__c,IsClosed,IsDeleted,IsEscalated,Is_Expenses_Claimed__c,LastModifiedById,LastModifiedDate,LastReferencedDate,LastViewedDate,Origin,Other_Problem_Reported__c,OwnerId,ParentId,Priority,Problem_Reported__c,P_O_Date_I_C__c,P_O_Number_I_C__c,Reason,Remark__c,Service_Center__c,Site__c,SLAViolation__c,Stage__c,Status,Subject,SuppliedCompany,SuppliedEmail,SuppliedName,SuppliedPhone,SystemModstamp,Type FROM Case where id=:apexpages.currentpage().getparameters().get('id') limit 1];
       return null;
   }
   
}