Bus to Kotor
 

Hi everyone, arriving by ferry from Korcula to Dubrovnik according to the schedule at around 630pm, would like to move straight on to Kotor but there doesnt seem to be a late bus that will allow this plan. Does anyone have anything to do with taxis or private drivers? Would this be a better option?

I would expect a taxi to cost a fairly obscene amount.

You might find a private driver to do it. Lots of Croats seem to do rentals and driving off the books, though you have a border crossing involved which might be a problem.

But the views are spectacular. Why would you pass through them in the dark?

(pre-booked) Taxis are not really that costly. And it's not unusual to take them across the border as Dubrovnik (more the airport than the port) serves as the major gateway also to the Bay of Kotor.
Ask your hotel in Kotor to assist you and give you quotes of services they usually use. I'd expect something in the vicinity of € 50.
I'd find that better than arriving at the port and having to negotiate a ride with one of the local taxi drivers.

A rental car is obviously easy to hire in Dubrovnik, but it can be tricky (and connected with an extra fee) to take the car not only out of Croatia but out of the European Union to Montenegro.

You may also take the public Vitaljina bound bus Dubrovnik dp 20.15 up to Gruda (close to the border) and change to a prebooked Montenegrian taxi at this place.
http://www.libertasdubrovnik.com/prigradski.pdf

You might want to try www.rome2rio.com to check out korcula to kotor if you are not wanting to stop in Dubrovnik.