I am going to be making a 3D Dora the Explorer doll cake October 27th for my duaghter's 2nd birthday. I could sure use some tips or any advice!

What I have planned so far is to use this dome shaped cake pan I already have, and I already have the Dora doll, but am feeling kinda lost, lol.

How soon should I start the cake? Should I freeze it so it will be easier to frost? What about filling?

Please help, I would greatly appreciate it!

Thank you!