Get there

We'll presume you know how to get to Croatia on your own. Once you're there, there are basically two different ways of reaching the island:

Option A - more or less if you don't own a car

Get to Rijeka (somehow) and ride Dubravka straight to Susak. Have no idea where to leave the car safe and low-cost. If you do, let me know please.

Option B - a bit more complicated, but you spend less time on sea

Get to Mali Lošinj town on Lošinj island (somehow) and jump on Ozalj to get on Susak. Make sure you go for a short ride (approx. 45 min), especially in heavy winds. Or bring a set of cards and ride solid 2,5 hours to either Ilovik or Unije on return.

Leave the car on a big parking lot just outside Mali Lošinj. I'm not sure about high season, but normally they didn't charge you for that. And if you worry about your brand new car, just do what we do - park the car next to a BMW or an Audi or any better car than yours. If you're a better car owner yourself, then you must be loaded and you can afford the costs.