i dont know if things have worked out for you or not with your mother inlaw issues, but if things are still bad you are not alone.
i have the same issues, not as big as yours, but my mother inlaw has been controlling at times with how we raise our child.
I have a 6 month old, and she tells me how to do things and says this is how its going to be rather than suggest things.
I now just let what ever she says which i feel is controlling go in one ear and out the other, and parent the way i feel is best.
You are the parent, you raise your son how you feel is best, and like every other parent out there in this world, you learn from mistakes as you go.
It sounds as if your mother inlaw is controlling your husband.
But you really need to stand up for yourself, mother and son. Your parents have as much right as his do to see their grandson and nephew.
And if that is too hard for your husband to grasp then maybe suggest a family counsellor. Because this is not a healthy relationship.
You should confront your mother inlaw about this, and get down to the reason why your husband and her dont want you mother to see her grandchild. Because she is the route of the whole problem here.
If i were in your situation, i would take my child and see my mother and other siblings when i wanted to. You dont have to sit there and agree to not seeing your family just because your husband and mother inlaw dont want you to go there.
My mother sees my son and i almost every other week-end. We spend the night with her, and my mom gets to bond and play with her grandson, and my 2 brothers get to play with their nephew. We arrange for all this to happen, and either i drive there, or she picks us up.
Mother inlaws always try to control things. Because every woman-i feel-who has been a parent already, thinks the know it all as to how to raise kids, and dont really want to even listen to a different way of doing things. Their way is the best and only way to do things.
Its really up to you and what you feel is best. and i would even agree that a 3 hour drive away from my child is a tad bit far even if he were with family..i would still rather be there than away from him.
Hopefully this can -or has- been resolved, like the poster before me said, it wont take over night to solve this, but maybe a family counsellor could help work this out.
good luck hun.