We're also going to Sveti Stefan in a couple of weeks. I had a hard time finding a good connection to TGD or TIV so we ended up deciding to fly to DBV and take a helicopter from there.
One still has to handle immigration in TIV before continuing to Sveti Stefan (they land outside Villa Milocer apparently) but at least the ~30 minute helicopter ride beats a 3 hour drive that can potentially get much longer when there's large queues at the border. The cost wasn't as bad as I was expecting, considerably less than Amanzoe despite the longer journey.