OK, so IABU... 
And yes, I know the reasons are "all about me", because it's me that'll have to do it all, isn't it... On my bloody own, whilst running my own (currently v. stressful) business, and attempting to bring up two children, run a house etc. with no help from anyone, especially DH, who's gone more than he's here up until Christmas. But thanks for making me feel even like an even shitter Mum than I currently do...
However, some good suggestions from others...
Our local soft-play parties are grimsville, and extortionate, for what you get (not much)... It's an option, but not in my top 10, and only as a last resort! Some friends have done it recently, and have felt v. ripped off and disappointed. Dunno they should be good, but at our local one, they just feel a bit, well... bleak...
The day out thing sounds like a good idea, but not sure we could stretch to paying for parents and children... Although if we severely limited numbers, and chose carefully... Would we be expected to pay for both parents and siblings? Or could we just say X plus Mum OR Dad...
Are they too young for it to be a trip to the Cinema and pizza afterwards? Obviously for whatever Disney thing is on, not SAW3. Same basis as the above? DD LOVES the cinema.
Outdoors, well, it's November so weather si hard to predict. I don't mind getting the waterproofs out and going for it regardless, but have several Mums of DDs close friends who aren't that way inclined...
Small numbers at the house... Gah... I did that for her third. It might have been more stressful than the fourth extravaganza, with the added downside of the house having to be tidy before they arrived and trashed when they left...
I really don't want to get into the situation of having to do a bash for every birthday x2. But maybe IABU in thinking that too...
It's bloody hard to limit numbers though... Now there's school friends in the mix...
db
xx