I have not really used the Yii mongo suite for this, I instead built my own since I didn't agree with the authors programming.
However it should be pliable to a foreach():
foreach($records as $_id => $record){
var _dump($record);
}
Should allow you to scroll through the records.
You can also use an array transferrer which will transfer the entire cursor to an array and scroll through it with default PHP functions.
I am not nsure what you mean by previous record but this will get the next record each time and if you are half way through a result set you will be able to get the previous record etc etc.