Don't come up with an adventure. Yep, this goes counter to a lot of other advice you'll find everywhere else.
you want is for each player to make up a life goal for their PC, like
'Find my sister' or 'Build a grand cathedral' or 'Kill the man who sold
me out and left me to die'
Then make up various forces in the area. Try to avoid 'if you don't stop them, the world will end' stuff.
Have a range - some forces might want to destroy a city. Others might just want to steal apples from an orchard. Write up three or so, ranging in size.
Then write up clues that would show these things are happening. Eg, creatures are stealing parts for a powerful arcane bomb in the night. Write up clues that could be found in a number of places - whether the players stay in a bar, delive underground or climb a mountain, try and write clues that could happen in as many of these places as possible - preferably all of them (though that can be hard).
Then write up how, if not interfeared with, these plans will happen over time.
Now do one or two more, per player, in regards to their own goals.
Finally, two things: accept that none of this material might get used!! The PC's might go and do something else. Let go of the idea everything you write will get used - don't fall in love with a piece of material and think 'this is gunna be so great when they do it' - because they might not do it. It's ok, setting wise it might be possible for it to happen another time. But if it's not possible anymore (it involves the king and the king died), just accept its gone. Sometimes its meant to happen, other times not.
And do not fear a split party!
(Sub note: Once again I wrote this somewhere else first )