In 1448:
England should own Gascogne, Normandie, Caix, and Maine in France. England lost Maine during the course of that year.
Lorraine and Province were united under Rene II, and Lorraine should have a CB on Naples as Rene had a claim to the throne. Province should be part of the HRE if this is possible. Naples itself was temporarily under the control of Aragon, although since it had been conquered only a few years before and would soon become an independent kingdom under an illegitimate son of the King of Aragon, its status would best be symbolized by vassalship.
The situation in Spain shouldn't change too much, as the Reconquista was pretty much on hold between the late 1200s and the late 1400s. Aragon should own Aragon (capital), Gerona, Roussillon, Catalonia, Valencia, the Balearics, Sardinia, the two provinces on Sicily, and Malta. What's left over should be renamed Castilla-Leon (but keeps the same banners, as the "Spanish" banners in EU were really those of Castile) with its capital at Toledo.
Serbia and Bosnia were both independent, but Croatia had been part of Hungary since around 1100.
All of Scandinavia is united under the Union of Kalmar
The Teutonic Knights own Danzig province.
The Russian pricipalities existed, but would be considered vassals of the Golden Horde. There were plenty of petty principalities, but the main ones were Novgorod (which owned Karelia, the Kola peninsula, and the White Sea coast), Pskov, Ryazan, and Vladimir/Moscow. Khazan became independent in 1444, Astrakhan in the 1450s.
In 1448, Burgundy owns Bourgogne, Franche-Comte, Flanders, Picardie, and Brabant (represented by Hainaut) and should be considered a vassal of France; Nevers was controled by a relative, so it could be considered part of that nation as well. Holland (the Hague province in EU) and Zeeland were owned by a close relative of the dukes of Bavaria and should thusly be given to that country, while Luxembourg was a possesion of Bohemia. As for Holland province and Freisen, the best I can think of here is to give them to Bavaria as well as they were pretty much dependent on (the real) Holland during that time.
Austria, Hungary, and Bohemia were all united, but Hungary and Bohemia were on the verge of revolt and should have high revolt risks and cause the united country to be on the verge of collapse. Maybe Hungary and Bohemia should be vassals of Austria?
Two Crusader states, the Duchy of Athens and the Kingdom of Cyprus, were still on the map. Technically there were still crusader dukes in the Cyclades and the Ionian Islands (Corfu), but these were already pretty much under Venetian control. Moldova definitely gets Bujak.
There were various petty Turkis states in eastern Anatolia, although the only one of importance was Karaman in south-central Anatolia. The decendents of Timur the Lame held sway over everything to the east of this, although the Timurid Emirate had the White-Sheep Turks (who were the rulers of Persia early on in EU) as vassals in Northern Mesopotamia and eastern Turkey, while the Black-Sheep Turks ruled southern Mesopotamia, Tabriz, and Azerbaijan.
The Moghul Empire should be re-named the Sultinate of Delhi.
By the way, I can't seem to get into your site. My browser locks up or crashes when ever I do. Do you just want me to post my list of prospective Byzantine monarchs here?