Some of this is going on for me, too. It is astounding how much of life cheating touches.
We may also lose our house, as you are.
My reaction to your post is to ask some questions of yourself. What are you comfortable with? Do you need to go, or is it expected?
And then, there is the after-affect: what can you live with in your heart and mind, after it's all done? Will you feel bad or will it not be very important anymore?
Or will it only be a few minutes and you can be done and "after", know you did a nice thing for your kids?
Do they want to go?
It's pretty rare-sounding to me to have supportive in-laws as you do and the very few who show me kindness anymore, I feel lucky to have that much.
Something I tend to forget is that they don't owe me anything, in the long run.
Do you know what's making you think you should do the visit?
I'm sorry for all the questions, but since I don't have a ton of advice, can offer at least things that help me make decisions of that nature.
I suspect you would be forgiven for not doing it, if that is an issue, too.
It's not either good, or bad, which ever decision you arrive at.
The one thing I will say, is that it could be a little bit of closure for yourself and kids to go through with the visit. And "after", you can have pride in doing a nice thing for everyone who was there.
A person is a person, no matter how small. -Dr. Suess
Perserverance and spirit have done wonders in all ages.