The best thing is for her to sleep in until about noon, get some coffee and lunch, play with the kids on the beach, then go back for a nap, then dinner, a shower, and put the twins down for the night. When you get done try to come in quietly so you don’t wake the kids.
I can’t imagine having to drag twin 2 year olds around an IM site. IM’s are just not that spectator friendly. You don’t want to have to worry about whether they are happy pre-race. Once you are in transition you just don’t have time to worry about them. And besides the fact that watching dad put on vaseline and body glide isn’t that interesting, they probably can’t see you. Once you are in a wetsuit you look like the rest of the seals. So you get the swim start, maybe 3 seconds when you are out of the water, if they run, maybe they watch for 3 seconds as you leave on the bike, then an hour or so of waiting for you to come back on the bike for 3 seconds, and then 10 seconds after the first lap and if you are lucky, they will see the finish.
I’m sure you are thinking I am dick by now. But after 8 attempts, this is how it works out for me and my wife.
So real suggestions, I don’t know that I would have them come down early with you. They can’t see you and all they can do is stand there until the start. Have her come down for the swim start. That can be pretty cool and the swim only lasts an hour. Once you are on the bike, go karts, the beach, eating, the hotel, etc. all work. If you are really intent on seeing the family during the race, pick a specific spot on the run curse where they will be, or you will miss them in the crowd. The big one for everyone is the finish, give a real estimate and hopefully she will catch you. And having help getting stuff back to the hotel is a good thing. But also be ready for her to be worn out and not so happy post-race, it is a long boring day for spectators.
At IMAZ last fall my wife came down with me early but I never saw her after i entered transition. She saw me come out, she saw me leave on the bike, she saw me get back, she saw me on both laps of the run, and she saw me finish. I never saw her that day until she got to our meet up place. So be prepared and don’t freak out if you miss her. I have no idea what she did all day, for all I know she spent the day with a new boyfriend.
MOST IMPORTANT - make sure you have a specific spot to meet post race and make sure it is a spot she can get to. IM sites can frequently change the traffic pattern the day of the race and getting to some spots may not be easy or even possible. Have her check that spot often in case she misses you finish. Trust me, there is nothing worse than being unable to find each other for a couple hours post-race. My wife and I got messed up at the Big Sur marathon and it was a two hour nightmare before we found each other.