You and your companions will need war-steeds if you are to travel across the plains of Rohan with any speed.
'We face difficult times not just in Langhold, but throughout all of the Wold as well. Théoden King has left those of us in the Wold without much support. I do not blame him! Rumour tells of great armies marshalling in the west, and we are spread too thin over too wide an area.
'If you desire to travel across the Kingdom of Rohan, you will need war-steeds for yourself and your companions. There are two things you will need to accomplish in order to obtain the privilege of such steeds. First, help in the support of Langhold. Once this city has been made safe, travel south along the road to Harwick, and you will be instructed in the skills necessary to safely and swiftly ride a war-steed.'
In order to obtain war-steeds for yourself and your companions, you will need to accomplish two things: complete the preparations for and defence of Langhold, and learn about mounted combat in Harwick.
The defence of Langhold involves a chain of ten quests that begins with a quest bestowed by Dala called 'The Wold.' If Dala has no more quests for you, search around Langhold for other quest-givers.
You can learn about mounted combat at the Tourney Field in Harwick.
Your companions have obtained war-steeds of their own, and are waiting to speak with you in Harwick, by the tourney ground near the stables.
Enstan is by the south-east exit of Harwick, in the Wold.
Your companions have war-steeds of their own and now you have heard that Enstan wants your help with something urgent.