Your garden sounds very similar to mine, long, thin and south facing. I dont really stick to the crop rotation that seriously, i just move things the yearly things about where i feel like it like potatoes, cabbages etc. Your perrenials will need to be planted somewhere your happy with as they will keep coming back - If your planning to get a rotavator then dont plant them smack bang in the middle of your allotment, things like that.
I have bramble right down one side of my garden to keep kids out and i get a good 1-2 lb of fruit daily at peak season too!
Ive just put a bed of asparagus down