LOTRO levelling guide : Level 40 - 50

At this point you've several options. Angmar, the Misty Mountains, Goblin Town and Forochel. Angmar has quests in Lehma-Koti (3S, 39.1W), Auguhair (3N, 39.5W), and South Angmar . Misty Mountain quests are mostly found in Rivendell or Gloin's Camp (24.9S, 3.8W). You should visit Goblin town at 43-44, finish book V and start book VI in Misty Mountain and Angmar and don't forget Forochel around 45-50 level. Of course ability to solo in areas will depend on class. Books VII - XI are waiting for you and also Goblin Town, and Rift.

You can also travel to the Ettenmores to take part in PvMP as part of the Free Peoples.

There are a number of instances that are available as well.