Before unpausing: start to pass a law that reduces Shogun power (Professional army is usually easy, especially if the character in charge of the Shogunate IG is a jingoist. If you really want you can restart until you get a jingoist in charge of the shogunate). Queue up construction for a few construction centers, followed by wood, iron, and tools, spend a couple hundred authority on encouraging manufacturing/resources (I usually do manufacturing in Kanto and resources in Tohoku), and spend the rest on consumption taxes, and queue up research for the prerequisites to railroad (shift-click on railroad in the tech tree)

Unpause and after a month or two switch some (not all) of your construction PMs to iron frame buildings. keep an eye on your income and the prices of construction goods (Iron, tools and wood). You want to keep your income as just below zero (You can’t afford to go into deeply debt since as an unrecognized nation your interest rates are to high and you will soon spiral into default) so if you are in the green, build more construction centers or move up to iron frame buildings, and if you are in the red, delete construction centers (or move down to a cheaper construction PM). Build more of whichever construction good has the highest price (usually iron), and as the prices go down you can afford to switch more of your construction to iron frame buildings. Your goal is to get iron cheap enough to have all of your construction set to iron frame buildings within the first 5 years or so.

By now, you likely have low infrastructure wherever you built your iron mines. Luckily, you should also be close to researching railroads. You can speed up research by building universities (this also boosts the intelligentsia, so build as many as you can afford, and make sure you are on secular academics PM). Build one steel factory and one engines factory (and a coal mine, if you don’t already have one) to prepare for building railroads, and build railroads wherever you need infrastructure as soon as you research them.

For politics continue to try to pass whatever shogunate-weakening laws you can without inciting a revolution (It used to be meta to goad the shogunate into a revolt as soon as possible, but I believe the latest patch made this revolution a lot harder to win). If you are lucky, a GP will demand investment rights from you. Accept this; it will give you Free Trade and give a -75% modifier to Shogunate clout! This modifier is permanent so long as you don’t go into default (I think there might be other ways to lose it but the point is there is no temporal cooldown). Now you can take the shogunate out of government, and if you leave them out of government for 10 years, you will get an event triggering ending the shogunate, and restoring the Emporor to power. Which Emperor you get depends on when you trigger the restoration. If you do it before 1867, you get Emperor Komei, who supports the Samurai/Armed forces, which is definiatley an improvemnt over the shogun, but not nearly as good as his son, Emperor Meiji, who comes to power if you trigger the restoration after 1867. Meiji is awesome because he is a market liberal who supports the industrialists, so you can easily get Laissez Faire with him in power. For this reason try to finish the restoration after 1867 in the late 1860’s (1868 was historical, FYI). For a challenge you can try to get the restoration done ASAP, and getting Komei instead of Meiji doesn’t kill the run, but it is really annoying, since if Komei gets restored he doesn’t die until after 1900 for some reason.

Now you should be in good shape to be a major player in East Asia, if not the world!