I did it recently, it was quite easy to be honest. Except I didn't get the achievement, of course.
1) Administration for the reform, Influence to abuse vassal feeding, Quantity because it's op, Religious for the CB and missionary strength, Humanist for less rebels when you go into coring spree.
2) I reformed the government asap and westernized soon after, using Genoa as the western neighbour. I had Crimea, Yaroslavl and Nogai as vassals at this point. Yaroslavl had half of Muscovy territory, Nogai had Kazan annexed.
3) There's no need for colonization, except for Taiwan which you can do late in the game.
4) Golden Horde is best Horde.
Here are the screenshots of my last game. I could've done it much faster if I abused vassals and truce breaking even more, but all I wanted was the achievement, so I didn't try to play it perfectly. I guess it's even possible to do a one tag WC as Golden Horde if you do.