OEM or aftermarket...fans are not cheap... personally i think aftermarket fans are better.
You are attempting a long trip with the car, you want to be comfortable and confident on the trip. If this is the case best to replace it all! I didn't hear you mention the expansion tank. That would be the area of focus for me. But you know your car better than me.
Some time ago...I started a discussion on what parts to take along on a long trip for emergency purposes.
My suggestion was expansion tank but that's NOT totally correct because the thermostat inside the tank usually breaks once the tank is removed and you'll need that! and your average repair shop won't have that little thermostat in stock.
There were many suggestions.
No matter what you've replaced
really best to plot a list of Indy shops along the route.