In December the tropics can be tropical. So while you might normally come to Bali for the beaches and the surfing you might find some of the best beaches are a bit too rough to enjoy some days. You might also find yourself in a thunder storm or two. There are lots of proper tourists visiting Bali, people who want to relax in a nice setting and wander round tourist markets picking things up to take home etc. The interior is less arranged for tourists - it's lush and there are some good walks and hikes, but the weather might be a problem again. Get some sound advice about whether or not it's a good time of year, I've not been that late in the year. For more ideas have a look at the next page on this site:http://www.worldreviewer.com/destination/singaraja-indonesia/12043/