Political map of the southern Balkans and western Anatolia in 1410. Disclaimer: The borders shown are often uncertain and conjectural; an effort has been made to be as accurate as possible and follow the relevant scholarship, but errors or omissions may still be present. Any help in correcting and/or improving this work would be greatly appreciated.
Own work using:

Basic map sources:
Haldon, John  "various maps" in     Palgrave Atlas of Byzantine History  
Hugh Kennedy, Historical Atlas of Islam, Map 11.3 "Byzantium’s Balkan neighbours 1350-1453: Serbs, Bulgars and Turks."
'"Atlas to Freeman's Historical Geography, Map of south-eastern Europe in 1401 AD
Southern Greece and Latin states in the Aegean and the Balkans:
Miller, William (1908)       The Latins in the Levant, a History of Frankish Greece (1204–1566), Category:New York:  E.P. Dutton and Company  
Setton, Kenneth M. (1976)       The Papacy and the Levant (1204–1571), Volume I: The Thirteenth and Fourteenth Centuries, Philadelphia:  The American Philosophical Society  ISBN:  0-87169-114-0. 
Epirus, Albania, Montenegro:
Nicol, Donald M. (1984)       The Despotate of Epiros 1267-1479: A Contribution to the History of Greece in the Middle Ages, Cambridge University Press  ISBN:  9780521261906. 
Brendan Osswald, L'Epire du treizième au quinzième siècle: autonomie et hétérogénéité d'une région balkanique
Fine, John Van Antwerp (1994)       The Late Medieval Balkans: A Critical Survey from the Late Twelfth Century to the Ottoman Conquest, Ann Arbor:  University of Michigan Press  ISBN:  978-0-472-08260-5. 
Northern Greece:
Vacalopoulos, Apostolos E. (1973)       History of Macedonia 1354–1833, Thessaloniki:  Institute for Balkan Studies  OCLC:   220583971. 
Boundaries of the Byzantine Empire:
Bakalopulos, A. (1962). "Les limites de l'empire byzantin depuis la fin du XIV' siècle jusqu'à sa chute (1453)". Byzantinische Zeitschrift 55 (1): 56–65. DOI:10.1515/byzs.1962.55.1.56.
Dennis, George T. (1967). "The Byzantine–Turkish Treaty of 1403". Orientalia Christiana Periodica XXXIII: 72–88.
specifically on the territories in Bithynia (Mesothynia/Gulf of Nicomedia):
Shukurov, Rustam (2016)       The Byzantine Turks (1204–1461), Leiden:  Brill, pp. 147–156  ISBN:  978-90-04-30512-0. 
Foss, Clive (1996)       Survey of Medieval Castles of Anatolia, Vol. II: Nicomedia, London:  British Institute of Archaeology at Ankara, p. 46  ISBN:  978-1-8982-4907-8. 
Ottoman Empire and Anatolian beyliks:
Kastritsis, Dimitris (2007)       The Sons of Bayezid: Empire Building and Representation in the Ottoman Civil War of 1402-13, BRILL  ISBN:  978-90-04-15836-8.
Constantine Plakidas