So I just tried "the jigsaw", and after making a potentially dangerous decision to have the starting CRFR tile with the road running east-west, due to table constraints (when playing with my parents, we play on the floor) meaning that I can't fit 9 tiles vertically, and then having to worry about where my cloisters were going (with about 20 tiles remaining, there were 4 of them still in the bag), then with 8 tiles remaining having to count the CFFF tiles in play (4, leaving 1) to leave myself a cloister space, and then needing my last 2 tiles to fit RRxx and RFRx holes and getting CRRR and CRFR, I managed to complete the jigsaw on my first attempt!
My mum got home a few minutes later, and after I explained the jigsaw to her, she said "if you try it again, you won't do it." She's probably right...