It's not a tough call at all, it's just a little tricky.
1- Before you even think of paying off your mortgage, find out if there is any prepayment penalty !
2- If it is an adjustable rate mortgage ( ARM ) find out the best date to pay it, ( that's usually few days before the interest adjustment date , and it's only 2 chances per year )
3-find out if you can get a line of credit, ( it's only about 45 Dollars a year to maintain ) but don't ever use your line of credit, except for emergencies, if and when you use it, pay it off in full and as soon as possible, otherwise, it's worse than a credit card.
I am speaking from experience, I had over 18 real estate transactions ( bought and sold ) , Paid off almost every house I bought, I used to have 250.000 Dollars line of credit,I used it to the tune of 140.000, paid it off and closed it. and I have written software, and managed other people money on a professional level.I have devised solutions to financial problems to help bankers and borrowers/home owners. Times are very hard now, so I use coal for heat like everyone else on this forum, and I am converting my hot water heater to run on coal so I can cut down my bills from 45 Dollars a month to just 20