First off, I have to say that I am not "officially" engaged yet. A ring has been picked out and is on layaway, we've booked a venue, picked date, and I'm starting to book other things too like my hair/makeup artist. We live together, and we're unofficially engaged lol. Just as good

I'll be getting my ring sometime in the next couple months. I hope it's ok to post here even though I'm not official...some of the other boards on here scare me and I don't want to get snapped at because my ring isn't on my finger yet.
This is my 2nd wedding, obviously, and his. I was widowed in 2009, and he was divorced in 2005. My fiance has two children from his previous marriage that live in Seattle with their mother (we live an hour south). Our issue lies in this, the ex wife does NOT have her driver's license and we have to do all the driving to and from seattle on the weekends we have them. It really ads up to a LOT of drivng. So we don't know how to deal with the day of the wedding stuff with them. We don't mind picking them up a couple days before, but since we are leaving for our honeymoon the night of the wedding, we can't bring them back home.
I'm totally not trying to be a diva, but I refuse to drop off my step kids at their mom's house on my wedding day, on my way to my wedding night with my husband. It's not fair to both of us. He agrees with me, but we are almost 100% sure she will not cooperate and have her boyfriend pick them up where we live. Just because she purposely goes out of her way to be difficult for us. So we're just not sure what to do. We want the kids to be in the wedding, but no one else can do the driving, and the majority of our guests are from out of town. Let me stress again, I'm not trying to be a snot about the whole thing, because i WANT them there. I just don't think that either of us should have to deal with her on our wedding day, because all that's going to happen is she'll put us in a pissy mood and I don't want that to start off our honeymoon.
We just don't know how to handle things, and I was wondering if anyone else has been in this same situation? I really don't want the kids to be left out, but if they're not there because she decides she won't bring them, all she'll do is bad mouth us and say we purposely left them out.
Thanks for your help too