I built 2 dollys for the EP Prams I made my kids from leftover scrap  and hardware from a big box hardware store.  They slide into the dagger board slot, which on these boats is pretty well reinforced by the seat design.   The dagger board tab on the one pictured is a little too short for optimal fore aft stability.   I am building one for the Skerry that is under construction.   They have worked very well for the 3 block walk to our local lake.  Iam working on posting pictures.