The store is a bit far from the airport, requiring a shuttle bus. You need to call for the shuttle and wait for it to come. If you're unlucky, the wait can be quite long, which is not a great experience.
Returning the car is better, just navigate to the store and return the car, then take the shuttle to the airport.
Insurance is recommended but not pushed aggressively.
The car I got was not ideal. I originally booked a Skoda, but ended up with a Citroen C3 with almost 40,000 kilometers on it.