My DIL gets on better with me than her own mum so i cant get a grip on this- but as others have said,it depends how old the children now are,also if they do actually want to out for day with her? What about a half day first,a cinema trip or something? Its essentially up to the boys own mum if she wants to let him,and though you know "she doesnt think highly of her" you still dont know for certain what she will say,so you still need to ask her,or let your husband or his own mum ask her,if you dont want to.its not something to "be at your wits end about"- you could actually just invite her over more often first,if thats how theyre all going to get to know each other better? (Some older generation do feel they have to be 'invited' fìrst) and maybe shes not as easy going as your own family,enough to just 'drop in'- indeed she may fear if she does that too much you may think shes trying to 'check up on you',and you would not like that,would you? You cant have it all ways,you either want her in the kids lives,or you dont,simple as that.if as has been said,you believe the kids are safe with her then start small,with inviting her round,maybe you could 'pop out' to shops etc while they play those board games,just for a bit,see how they all are together? Then park or cinema trips,or even for a,dare i say it? a happy meal? Or pizza? Then longer trips as its getting nearer xmas?im sure if you& hubby say you'd like to help with advice on where to take them she can compromise?(pantos or christmas shopping,or some such?) Good luck and enjoy the peace& rest while their all out,or get a chance to wraps christmas gifts in peace?