Am I obligated to maintain ties of kinship with my deceased husband's family if they do not ask about us and treat us poorly, and is it permissible for me to ask them to receive my daughters in my home instead of visiting them?

Maintaining kinship ties holds a great status in Islam, and whoever does so will be rewarded for it, even if the other party does not reciprocate. If a visit causes embarrassment, it is not obligatory for you, but you must deal with them kindly and open your home to them.