Upvote:1
It will depend on whether you need a transit visa for the Schengen countries (which you can find here) but if you don't you are good to go.
It is allowed to return to an airport within the Schengen area as long as you do not need to leave the international zone and you do not need a transit visa.
If you do need a transit visa, you can apply for one or ask for a multiple entry visa in the first place and hope you get it.
Remember that you will need a visa and not a transit visa if you have two separate tickets and need visa for the Schengen area.
On the other hand, you will likely find more than enough to do in the Schengen countries and if you do not want to risk not being allowed back into Schengen, you can plan your journey such that you do not leave the zone.
Or arrange your return journey home such that you do not need to return to the Schengen zone for your stopover/transit airport.