In my sketch, without the yard, there are six LH switches, six RH switches, one 45 degree crossover, and two 90 degree crossovers. I believe the D-264 is approximately 9x5, but that is using Super 0 track which I believe is 0-36. You would have to modify the plan for 027-031, but you might still need the same amount of space to ensure that the grade isn't too steep.
I think the peninsula should be 5-6 ft wide (allowing 2.5 - 3.0ft reach from either side), depending on the elements you want to fit inside the space.
There is a buy/sell forum here, I have had good luck acquiring additional pieces I needed for reasonable prices from people who enjoy helping another guy out. With this size of a layout, you may want to get a bunch of 022 O gauge switches that you can supply with fixed voltage and switch remotely.
