There is a huge soft play area, with a smaller area for under 2's.
There is a smallish swimming pool (which will be quiet off season).
They do a morning club where you can go and paint and stick and stuff if you want to do that sort of stuff.
There are a couple of playgrounds IIRC.
There is evening entertainment.There are 2 entertainment complexes. The one near the main entrance has entertainment aimed more at adults (although children are welcome), a smaller one in teh other half of the park has kiddies entertainment. She will probably be a bit small to appreciate it fully but may enjoy seeing "Rory" the tiger et al. if she isn't scaredby that sort of thing.
All of the above is free.
If you want to get out and about there is a donkey sanctuary which si cheap and cheerful at Holt I think.
As I say Banham zoo and another one I think.
I would not recommend pleasurewood hills at her age but there is quite a big fairground type place in Yarmouth at the far end. Just before that though there is a smaller fair place for littler children which is OK.
Honestly. katyMac is the person to ask about days out round there. She has all the local knowledge.