I had quite some trouble with cramp and getting solids down on my first attempt, i tried a few things on my second attempt which really seemed to work:

Hot marmite drinks- full of salts and b-vits
SIS Rego - Easy to get down, easy on stomach and a protein source

On the day my stomach was much better and I had no cramps at all, which considering it was hot and clear is a miracle for an easy cramper like me.

Smoothies were a bad idea, i thinks its the fructose/sucrose - If i was to it again I would cut out anything sugary as it seemed to cause sickness.