Steel Tiger
Senior Master
The sequel is supposed to cover the time between The Hobbit and LOTR. Not sure what was going on in the interim. Maybe start of with the fight with the necromancer in the tower (which is mentioned in The Hobbit) and go on to handle Suaron returning to Morder and the actions of the Rangers to protect parts of Middle Earth, including the Shire.
I mean, there are references in LOTR to some events that would've happened off the main plot in The Hobbit and before LOTR, but I'm not sure how much Tolkien fleshed them out (I haven't read Unfinished Tales and some of the other writings)
The sixty year period between the end of The Hobbit and the beginning of LOTR is something of a Gandalf and Aragorn tour de force as they search for Gollum and investigate the return of Sauron and the Nine to Mordor. And then there is the whole situation with Balin reoccupying Moria. Lots of fights between dwarves and orcs.