Tips for maintaining muscle for my holiday in Bali?

To avoid muscle loss, I would advise that you get on or stay on creatine, eat high protein - so meat, fish, eggs, chicken, etc - and otherwise stick to mostly non-starchy vegetables (not too much rice - I think they eat quite a bit of rice in Bali) and a couple of pieces of fruit.

If you are unlikely to enjoy some of the foods that are available there, then don't forget to take protein powder and/or meal replacement products (MRPs).