Congrats
Brinniel for the milestone!
Otherwise I'm afraid that
Macalaure is right. The party is most economically carried to Mirkwood by the eagles and Beorn can be written off from the battle... Sadly so.
But it could make also a fine action-movieish (?) introduction to show Beorn shifting shape in an introductory action-scene! It would just require lots of explanations afterwards and an action movie would not bear (sic!) that...
Why I speak of an action movie? Well it's not going to be a Bergman-drama anyway...