Basicly there are keyframes (KF) every 10th frame - I didn't have any particular picture of what the final result should look like so I kept all the KF as they came up (it helped a lot).

2 "walk cycles" are used - first when she's crawling and second one while walking up the stairs (for that I made a python script that mirrors all necesarry parameters and offsets them in directions I need - so it takes "no time" to see the result of some "walk cycles").

Overlaping of Jessies takes about 2 seconds - I mean same poses are applied to both of them for 2 seconds before "swap".

I found that working with IK on hands was not easy (that was the first time I used it and it was quite difficult).

I made already 15 seconds longer animation where at the begginig she wakes up, turns around and starts crawling but it still needs some tweaking - and it's not easy while IK is on - so maybe I'll add 3rd Jessie with no IK at all).