I have twin daughters (2 sons, too) who live no more than 15 minutes away, and they involve me in their's and their children's lives and routines, invite me on holiday (I don't always say 'yes' and they don't invite me every time) and we have what I think is a great mum/daughter relationship. Both have had problems conceiving, both had IVF, both have twins, and both were fortunate to be successful first time. They've faced tough times that I've felt helpless to be able to assist with, but come through them as strong women and mums, and I really admire them. They are close sisters, and close to their older brothers, who still delight in winding them both up, but are protective towards them, too.
I love them asking, when their children misbehave, 'was I ever like that?' I'm pleased to be able to reply 'oh, no - you were ten times worse!' 