All of my resources are for England and northern Europe, and I'm not sure what the important differences are between locations.

Your friend should check out the SCA's Slavic Interest Group and their mailing list.

If he is looking for an SCA name, point him at the Dictionary of Period Russian Names. If he wants a 14th century byname that indicates that he is from Novgorod, he could go with "Novgorodets."

I am unsure whether Compleat Anachronist #35, "An Introduction to Russian Costume," would be helpful, but it might have some useful patterns. You can order it from the Stock Clerk.

Other potentially useful online resources:

• Life in 13th Century Novgorod
• The Novgorod Chronicle: Selected Annals
  
• Novgorod Resources
  
• Novgorod State United Museum
  
• The Art of Onfim: Medieval Novgorod Through the Eyes of a Child
  
• The Squirrel Fur Trade in 14th Century Novgorod
  
• Patterns and Instructions for Medieval Russian Costumes
  

Some books to look for:

• Novgorod in Focus: Selected Essays by H. Birnbaum
  
• Chronicle of Novgorod, 1016-1471 by W.K. Hanak
  
• Wooden Artefacts from Medieval Novgorod by B.A. Kolchin
  
• Novgorod the Great: Excavations at the Medieval City by M.W. Thompson

Also, you can find some interesting information at site Tozhe Gorod. Unfortunaly all articles in it in Russian. Here are some materials on Russia: http://tgorod.ru/index.php?topgroupid=2&subgroupid=5&groupid=7

Sorry for my English

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