F, I am going to be the outsider here and suggest that you do plan to go together. If, come March, you really feel like you don't want to go (because you will feel horribly uncomfortable, not because you think you need to not go in order to further some sort of strategy), you can always politely back out and allow your W to take the kids herself.
Others may disagree, but I think that if you can set aside your differences (as your W seems willing to do) to create wonderful memories for your kids, that can only be a good thing. Maybe you and W will have a great time, and the 2.5 hour drive will be a chance to relax and reconnect and even create pleasant memories for you and W. Maybe it won't. But if you go into it with an open mind, you never know, it might be a great family outing.
That said, I think that they way your W presented it - insinuating that you would not be allowed to have the kids on your birthday if you didn't give her what she wanted - was not cool, but let's just give her the benefit of the doubt for the moment. After all, she did text you with another possible solution that sounds much more thoughtful and reasonable.
Just my $.02.
me: 44 XH: 42 M 11 years D10 and S8 Bomb drop 9/27/13 D final 7/1/14
