Well with given time At Kawr it's Highly impossible to get a general ticket. But there's a small trick Get A Counter Ticket And Enter Your Destination As Vasco/MAO this way You Get Reservation upto Kawr + Part Unreserved Till Vasco/MAO in Your Same Reserved Ticket Only. Never think about getting On board tickets it's risky In most possible scenario Tte will Fine you.
And Most Probably AC Class bw kawr-vsg-kawr will be shut. If online it's impossible UTS Doesn't lets you buy ticket from inside and IRCTC doesn't let you to buy part unreserved tickets