Book your hotel early and for airport it is better to get the Hotel pick up. They are more expensive( a lot more by Sri Lankan standards) compared to under and pick me. But the reliability of the hotel airport rep who will pick you up as soon as you leave the customs area and put you in the hotel car.
As for Maldives, it depends on where you want to stay. You can stay in a resort close to the airport which means you take a short speed boat ride. If you want to stay further away from the airport, then you either take a seaplane or a domestic land based flight. There are about 5 to 6 flights per day from Sri Lanka to Maldives.
It is not cheaper in Maldives and you would find it almost impossible to get a resort under USD 200 in Maldives.