Before you unpause the game, set your minting to 100%, start building a galley in Thrace and an army in Greece (1 cav 2 inf.) and move towards centralization. If you get a revolt in stead of a stability hit, restart.
Once you achieve this, keep on a galley in the build queue in Thrace and keep a look of the Ottoman forces in Greece. As soon as the cross the strait to fight the Timurids and your new 3 regiments army is in Thrace, declare Reconquest war on the Ottomans. If Wallachia does not honour the call, restart/reload.
Once you achieve this, you should have around 9 galleys and 3 cogs. Leave them on port. Start moving your armies to Ottoman held Greece and start sieging two or three provinces a time. Send one infantry regiment to the province to your north in order to deprive Wallachia from that siege. Do not set siege the Ottoman capital, that's where their fleet, if you siege it, their fleet will sail out, giving their army enough time to leave Asia.
Always keep a galley in the build queue until you reach three or four above the Ottoman fleet.
Keep an eye for Bosnian/Serbian armies. Wallachia should take care of them. Your aims should be to siege the Ottoman, Bosnian and Serbian lands and at the same time, destroy the remaining/new armies in Europe.
Take a look at the Ottoman armies trying to move from Asia to Europe. When they are about to cross over, order your entire fleet to sail towards the Bosporus strait and then back into the port immediately (use SHIFT+Click to place this orders). You may order them to patrol, but your fleet risks getting intercepted.
Once you have around above 13 galleys, stop building them and set them to patrol the straits (Bosporus/Thrace). At this stage, you can already siege the Ottoman capital.
Eventually you should have occupied all of Ottoman Greece, Bosnia and Serbia. If Wallachia occupied any province, place one regiment of infantry in this province since they will eventually bail out signing a white peace.
You should also be able to sink their fleet eventually.
Once you did that wait a little bit. You have three cogs and two 3k armies. While they have all of their armies trying to cross the straits, you can sail an army to their rear and start sieging. If they come after you, load your armies to your cogs and get the hell out of there.
The Ottomans will eventually go bankrupt. At this stage, make a couple of raids assaulting their forts. Once you've taken a couple of province in Asia, you should be able to sue for peace and take all of Greece (except for their capital) and one province in Asia.
Build up your armies and navy to match your capacity.
After you've done this, take a look at the Christian holders of your core provinces (Achea, Corfu, Rhodes, Cyprus and Trezibond). If you can, you should be able to take at least one of them.
After your truce with the Ottos is over, Dow them again. If you are playing Heir to the Throne, make sure to DoW to reconquer them at the same time that you DoW other muslim countries that are allied to/guarantee them. If you are using the latest patch, you should be able to annex them.
Once you've reconquered all the muslim held territories that you had a core on, you'll be one of the most powerful countries around with no infamy at all. Invade Venice and take the provinces in which you don't have a core on, in order to use some infamy. After you've destroyed their armies, try funding patriots in the remaining areas of Greece that are still held by Venice and in which you have cores on. They will defect to you, eventually. If you can, ask Hugary and Aquilea for military access in order to occupy Terviso and "persuade" them.
Focus your budget sliders to get +3 stability and government tech 4. At first, at least, take the National Bank Idea in order to get rid of your the inflation you got building your navy and supporting your army.
Mid term goals (before 1500) should be:
- Build a Centre of Trade in Thrace
- Take over Judea
- Take over southern Italy and up to Rome taking advantage of some GREAT missions that Byzantium has
- Take over Mecca
- Trigger the "pentarchy" (own Judea, Rome, Thrace, Aleppo and Alexandria and convert them to the orthodox faith)
Before 1550 you should be westernized. After you do this, go east as much as you can before 1650. In 1650 you'll lose the "Holy war" causus beli, making conquering non Christian lands very cheap. By that time, once market places have been built in most of western Europe, your spice provinces in Arabia will yield a lot of money and you will probably be technologically on par with most OPM western European nations.
Let us know how did it work.
Good luck!
EDIT: Here's an example of a game I had by 1604 (notice the Italian Peninsula). By 1650 India was also conquered as well as South Africa. A realistic goal would be to keep every European power west of South Africa, colonizing by yourself the Dutch East Indies, Australia, Taiwan, the Indian Ocean islands (including Madagascar) and the Philippines. These would be you only "overseas" provinces as the rest of your empire (including South African territories) should be connected to your capital by land.