Retrieve Permission Set Access using standard Salesforce objects

1. Query to retrieve Object Level Permissions

SELECT Id, ParentId, SobjectType, PermissionsCreate, PermissionsRead
, PermissionsEdit, PermissionsDelete, PermissionsViewAllRecords
, PermissionsModifyAllRecords, CreatedDate, CreatedById, LastModifiedDate
, LastModifiedById, SystemModstamp from objectpermissions 
where parent.name = 'PERMISSION_SET_NAME_HERE'

2. Query to retrieve Field Level Permissions

SELECT Id, ParentId, SobjectType, Field, PermissionsEdit, 
PermissionsRead, SystemModstamp from fieldpermissions 
where parent.name = 'PERMISSION_SET_NAME_HERE'

3. Query to Retrieve Apex/Visualforce Page/Tab level Access
SELECT Id, ParentId, SetupEntityId, SetupEntityType, SystemModstamp 

FROM SetupEntityAccess

WHERE parent.name = 'PERMISSION_SET_NAME_HERE'

4. Query All system permissions (add all columns from object as needed)
SELECT Id, PermissionsModifyAllData from permissionset 
where name='PERMISSION_SET_NAME_HERE'