Antique blue mason jars with baby's breath on shepherd hooks along aisle, beach wedding. Shepherd hooks would be easy to put on either side of where the bride and groom stand, wrap in nice ribbon, put some flowers on it, call it a day.
If you want to see a lot of places in Costa Rica, the best way to do it is by staying at hostels. They can be very unique and you can meet people from all over the world. Sometimes they can be as cheap as $5 per night.
A Detailed Guide to Visiting Rio Celeste, the Sky Blue River