Well, Balaam's story tells us how not to determine God's will. He knew God's will but wanted God's will to agree with his will.
But when we face a decision where BOTH choices seem right and neither conflict with what we know to be right, it becomes far more difficult, and I think that's where you are right now.
Yes, prayer is key, talk it over with God all through the decision making process.
Then list all the advantages and disadvantages of each choice.
I know when I was faced with this situation about two years back, things started moving in favor of one choice, was that a "sign"? I didn't know, I couldn't sleep all night, but I prayed -- Lord, if I'm heading down the wrong road PLEASE stop it, PLEASE! I don't want to go down a road that you don't want me on. The very next day the door was thrown wide open for me to take "that road".
I could tell many stories of God's leading. Often I really didn't know why God led us down certain roads as they weren't always smooth roads, yet looking back, yes, all things do work together for good to them that love the Lord.
Pray -- God, You have to show me, for I didn't know what to do.
Just pray that He will not allow you to take the wrong road, you want to walk in His will, and that he will help you make the right decision and lead you each step of the way.