Well, he doesn't exactly enjoy walking, and he is pretty encumbered, especially when he is carrying the staff of the Vonindon, which is normally strapped to his horse.
On the other hand, it's better than having an unnecessary fight, he is curious whether it is possible to reason with trolls, and he would like to find a local guide to the Evermoors.. So on balance, yes, he probably would be prepared to give up his horse for a day or two..