Travel
While in Kauai, it is best to rent a car. There is a public transit system but, it isn't recommended as you will spend precious time waiting around. In regards to staying on the island. Please please please stay on the SOUTH side of the island. The best option is to stay in Poipu as it is so close to the venue. If you choose to stay on the North side of the island, there is a risk for road closures due to mudslides. As, winter in the rainy season on the island. The most economical option would be to rent a condo or house and split it with other guests. This will also allow you the option to make some of your own meals, as most include kitchens. There are plenty of places to find on Airbnb, Vrbo, or homeaway.
If this isn't your style there is a list of bed and breakfasts, and hotels to stay at.