The historical novel Sworn Brother by Tim Severin continues the tale of Thorgils as he travels through the viking world. The backdrop of the book is his friendship with Grettir, who becomes his sworn brother, but he still visits places from Iceland to Finland and even Constantinople.
As with the first part of the book, the book is more of a collection of loosely connected tales than one big story. And the main purpose of the individual stories is not so much to describe the development of a character, but to relate the realities of a world long gone. In this, the book is a textbook on the viking age masquerading as a saga.
I suspect if you do not like this kind of book, the lack of character development will put you off. While characters are not particularly thin, few of them are deep with a rich personality. On the other hand, if you are looking for a historical novel on the viking age, go for this series.