There's many different ways to decorate a pumpkin, but have you ever considered having your kids do it in a way that would help them with their fine motor skills? I did last year, and decided to have my daughter paint a pumpkin using q-tips. This helps to prepare children for writing.
All you need is a pumpkin, a plate, some paint, and q-tips. I decided to use a tiny pumpkin for my daughter doing this. It was perfect and turned out very cute!