Not sure, but my general experience in this area is that there always is a way. Local mini buses, or fix a good price from a cab to take you to the border, walk across and take a cab from there to Shkoder. Or find a good spot to hitchhike. Good luck!
I would recommend hitchhiking to the border crossing by foot and hitchhiking again.
If you and your friend are more comfortable with public transport you can go to Podgorica with the train (that's about a hour) and then take the bus to shkoder which is about 2 hours. So with transfer times maybe 4 hours. Here are the train times from about 2 weeks ago. Not the best picture. Sorry for that.
Train and bus are still a long travel time. So maybe ask at the bus station if there is a bus to the border. I couldn't find any online. Or if you have the money a taxi.
Hope you are enjoying Montenegro I was there about 2 weeks ago, it was very pretty and the people seem to be very friendly.
Thank you both for the replies. Looks like hitchhiking and crossing on foot will be the way to go.
Someone in our Hostel mentioned that there was a ferry across but we couldn't find any information or any other source that this was true and they weren't sure were from so sounds like that ones a skip.
Montenegro is beautiful though, wish we had more time here.
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