What happens in Chapters 19, 20, and 21 in "Adam of the Road"?

Adam decides in Chapter 19 that the best chance he has of finding Roger is to go back to London, where Roger had planned to spend Christmas with the de Lisles.  though he has no harp, he makes up songs of his own as he travels, and meets a kind peddler with whom he shares stories and food.  When Adam arrives back at Westhumble Lane, the place where Nick had been stolen, he gets news that Roger has been there and has indeed gone on to London.

In Chapter 20 Adam arrives at de Lisle House in London only to find that Roger has gone with Sir Edmund to Wales and will not be back until May.  Disappointed, Adam spends the holidays at the House, which is habited only by a few servants, as the de Lisles have gone to Ludlow.  He wanders the streets of London with Matthew, the bailiff's son, seeking amusment during the long winter, and one day runs into Jankin, who reports that Nick has run away from him, about two weeks ago, at Gornambury, near St. Alban's.

Adam returns to St. Alban's in Chapter 21, and finds that although Nick had been there, it was too difficult to find food for him, so Perkin has taken him along on to Oxford.  Although his shoes are worn, Adam sets off for Oxford, sharing songs and stories along the way.  He meets a steward, who, impressed with Adam's minstrelsy, advises him to see a friend at Oxford who might help him study there.  Barefoot now, Adam approaches Ewelme, near Oxford.