On Krypton, there is a Monster Island that has their versions of Godzilla, Rodan, Mothra and Ghidorah (chose your era if you want). Since the Kryptonians had put a force field around it to constrain the monsters, they survive the explosion. They and the monsters go hurtling into a yellow sun. It takes them a bit to escape the gravity and the group gets blasted into hyperspace.
Now, their physical characteristics and powers are magnified by the same factor as Kal-els characteristics are magnified to be Superman. They gain the usual powers also on top of what they already have.
So they hurtle into ( as a surprise):
1. OA - which has the 36 Guardians and 3600 GLs of classic times (there for a meeting).
2. Galactus's world ship - slam through the sides.
3. Bop into Dormammu's dimension
4. Land on Apocalypse
The landing sites have no particular info as to specific weakness such as Kryptonite, magic, red sun, etc.
How does it go? The monsters engage in their usual let's go to a city and stomp around.