Long story vv short - I have a difficult relationship with ILs, they are very disinterested in our lives and the DCs. Many stories I could tell but I don't want to bore you! 
They visit 2-3 times a year for 2-3 days at a time. They're very high needs and rather than viewing these visits as an opportunity to spend time with the DC and be involved in our lives they require constant entertaining - days out to 'destinations', meals out, etc. MIL is a fussy eater and catering for her is a headache. They can be very rude and I end up biting my tongue till it bleeds to attempt to keep the peace. I generally find their visits stressful, exhausting and unenjoyable but usually just grin and bear as I want the DC to gave a relationship with their grandparents.
However, they want to come in the Easter holidays and it's just too much. My mum died on Good Friday last year and I'm really struggling with the impending anniversary, especially as we will always now have two - good Friday and the actual date. I'm struggling with the fact that my wonderful mum is gone and my kids are stuck with the rubbish grandmother whose interest in them is minimal. I can't see that being improved by her presence. In addition I've been quite ill and am struggling with keeping up with Uni work - I have four essays to write over Easter and am barely coping with kids, housework and studying, never mind all the additional work their visit will bring (they stay in a hotel but there is food, and extra cleaning as mil is hypercritical).
I just don't want them here. I want peace and quiet, time to study, some family time. No firm plans have yet been made or anything booked. WIBU to ask dh to ask them to come later in the year? Or if they do insist on coming, WIBU to tell dh that he's responsible for cleaning to her standards and feeding them whilst they're here, and that I will not be trotting off on day trips but staying home to do some studying in peace? I don't know if either option is U or not because I'm obviously biased by finding them such hard bloody work and always dreading their visits!