The route is called put Oluje - named after a military operation in 1995, "operation storm" - and is well marked. It is a combination of makadam roads, old shepherd paths and hiking trails.
There are several mountain huts and shelters along the way, most of them have water and if they are closed, there are enough camping spots nearby. It is possible to hike from mountain hut to mountain hut and it is probably also possible to arrange that they're open, but then you need to plan ahead. Something I don't like. I'd rather bring my tent and see what the day brings. If you plan this hike, you can do it in a week. Mind that there are no possibilities to buy food along the way.
Also, it is possible to make this even more challenging if you choose to follow the mountain ridges instead of the main track. This will take more time, is more exposed and physically more demanding. I wasn't always able to stay up on the higher variant due to the weather, but the trails show up on Open Street Maps, so in theory you should be able to follow them. Do not expect a real trail though, often there are no paths at all, but just a line on your GPS.
For stories from the trail, check my blog EVAdinarica Project
Note that this route crosses the border without passing a checkpoint. From Buško jezero I went back to Zagreb, had no problem at the border, but if you want to "check in" oficially, you can also descend from Kamešnica to Planinarsko Sklonište Sveti Mihovil and pick up the Via Dinarica to Kamensko.
The terrain is very exposed, dry and extremely hot during the summer. Water is scarce, in summer the cisterns at the huts might run empty so be informed.
After Troglav there is a mine suspected area. It is well marked, but you need to be careful here.
Waterfilter, rope, plastic bottle (or whatever you can use to get water out of a well)
Tent (not all huts are open)
Stories on my blog: EVAdinarica Project
If you're taking the bus, ask the driver specifically if you have to transfer somewhere.