Unless there are health reasons she can't travel, or unless she is caring for a spouse who can't be left alone, etc. your MIL can come to you every other Christmas. If she can't afford it, which would be understandable if she's on a fixed income, offer to pay for her flight (and for a nice hotel near you if you don't have room). Those costs, added up, probably are going to be less than gas, meals out when on the road, Amazon shipping, and STRESS for you. A 14-hour drive each way? That would be a non-negotiable no for me.
I figure the folks who are not dealing with kids can be the ones to travel. Some older folks just cannot possibly imagine the idea of a holiday that they themselves do not host, but you may be able to sell her on this by pointing out that she would not have to cook or clean at all. If she has other grandkids living in her area whom she says she just must, must be with at Christmas, well, point out that it's only every other Christmas, or every third one, or only until your children are older. Or say that you will briing the kids up for a great summer vacation when there is not the pressure of presents, potentially awful weather to drive through, etc. Does she really want her family on the road for 14 hours with every other nutcase driver in lousy weather, rushing to get to her?
I think families get far, far too wrapped up and invested in "We must be together on Christmas DAY. It must be Dec. 24 and 25. The children/grandchildren must be physically present with grandma/grandpa/cousins/whomever." The calendar date of Christmas is "sacred" only in a religious sense; there is no reason whatsoever that families have to be in one place at one time to celebrate it; celebrate whenever you like and in a way that does not make you dread and hate what should be a calm and rejuvenating time.