The great thing about Prune is that one leans how other students are taught...Flight bags, what are they?!
Personally I put everything I need (except my chart) into my grow-bag. Chart is stuffed down the side of my seat and I currently use a piece of laminated paper strapped to my knee and a chinagraph pencil to note down ATIS and ATC instructions. Headset case I leave in the clubhouse...
...but there is very little spare room in a Grob...