I am just about ready to explode, or at least dribble with despair... Please help me see if I'm being unreasonable...!
Back-story, I have very hands-off parents, they live 200 miles away, I left home at 18 and never went back, and I don't feel we were particularly close ever. I see my parents once or twice a year, we drive to them once a year, they never visit us "for the sake of it", just pop in for a couple of hours max when they're driving past for a mini-break. Their choice, fine, and in the past they made it clear that for whatever reason they weren't particularly keen on DH ("I suppose congratulations are in order" was the immortal phrase when I went, alone, to break the news about us getting married (in our late 20s, owning a house, both with jobs etc...)) DS is first and only grandchild, but they're just not interested, send money for birthdays, no thought of presents. Again, fine, their choice, and maybe they're keeping at arms length so they don't get too hurt by seeing so little of him. 
We went for a flying visit in August, as my grandmother is ill, we made the 3hr drive down, stayed from Saturday midday until Sunday morning, saw my parents for a couple of hours (after they said they had to go to a dog show to look at dogs during the day). The visit went well, so I said we'd try and get back there in half term, even if DS and I went by train alone. Mum even rang and checked when half term was when they were thinking of booking a holiday to make sure it didn't clash.
Fast forward to yesterday, I rang to check it would be ok to go down from Thurs through Sunday. "Just you two isn't it" said mum, No, DH has got a couple of extra days holiday due to Xmas office closure so he'll be coming too. Cue audible cats-bum face, snippy responses, and virtually booting me off the phone. Obviously DH now doesn't want to go down at all, I still feel a bit obliged to go down, as my grandmother still isn't well and won't get any better, the city is nice, DS'll love the museums and the Castle, so it would be cutting off nose to spite face time not to go at all, but it'll be walking on eggshells the entire time and umpiring between the passive aggressive camps of parents and DH.
I think I'm being objective in saying that my parents are only happy if everything's on their own terms - eg. when we last went down, we couldn't travel on Friday eve as planned because I had work, and was told "Is it worth bothering to come at all" by my dad. Or am I being oversensitive?
What's upset/annoyed me most is that I was so surprised and pleased that mum was making arrangements to fit with us going down, but now it seems we're not particularly welcome.
Gah!