That is where my mind went I cannot get much beyond thinking ruffles and floppy hat with feathers in
Well, thinking quickly, starting from the feet, and assuming you can find stuff in charity shops and have time...
Plain shoes. Knee socks. Pair of plain loose trousers (Tracksuit perhaps?) cut off at knee and gathered in at the hem (a simple running stitch would do it). Loose white shirt with baggy sleeves. Waistcoat, preferably cut from something that looks like tapestry (a cushion cover, or small curtain?) Ruff - net curtain perhaps, a long strip gathered along one long edge with long running stitches and fixed round neck, fastened with safety pins (with perhaps a cardboard donut shape underneath to support it). Hat - big circle of velvet, gather round the circumference and draw up enough to fit the head, sew a feather on.
Can you tell, I like fancy dress?
My sister once had to go to school in 'Medieval' dress, my Mum made her a very shapeless dress out of some rather itchy hessian. I think even at 6 years old, my sister resented it a bit....