The Presidential Succession Act of 1947 states that this is the order of succession: president, vice president, speaker of the House, president pro tempore of the Senate, then Cabinet officials who were confirmed by the Senate in the order their department was added to the government. So...
1. JD Vance
2. Speaker Mike Johnson
3. Senator Chuck Grassley
4. Secretary of State Marco Rubio
5. Secretary of the Treasury Scott Bessent
6. Secretary of Defense Wino Pete
7. Secretary of the Interior Doug Burgum
8. Secretary of Agriculture Broke Rollins
9. Secretary of Commerce Howard Lutnick
10. Secretary of HHS RFK Jr.
11. Secretary of HUD Scott Turner
12. Secretary of Transportation Sean Duffy
13. Secretary of Energy Chris Wright
14. Secretary of Education Linda McMahon
15. Secretary of Veterans Affairs Doug Collins
16. Secretary of Homeland Security Markwayne Mullin
If Todd Blanche is confirmed as AG he goes between the Town Drunk and Burgum, and if Keith Sonderling is confirmed as Secretary of Labor he goes between Lutnick and Kennedy.
Please note: This only applies if more than one official becomes unable to take over the presidency at the same time. Let's say that Trump finally drops dead of hamberder abuse. Vance becomes president, right? Vance will then choose a new vice president, who will take Vance's place in the line of succession. If Vance is then impeached for screwing one of the couches in the Oval Office, they're not going to elevate Johnson to president only to later impeach him for his porn fetish which would cause Grassley to become president. After Vance is impeached for couch fucking, the new vice president will take his place and that individual will appoint a new vice president.