I started with graded exposure for my agoraphobia in April, and am now managing to see places I haven't seen in years. When I started my circle was about 3 miles at best but now it's about 7 miles and very slowly but surely expanding. I am getting a real buzz from this, the successes are amazing, yet the horizon is still frightening. However I want to help anyone in a similar situation with a bit of advice which I have found VERY useful.
I am pushing myself out to my boundary, then a little further, and waiting there with the engine off until the anxiety drops by about half. Then repeating this next day or the day after. Repeated hits is the way to knock the anxiety to the ground. But the thing which I have found extremely useful is Google Maps, particularly Streetview. With this I am crawling along the road beyond my stopping place before I go out, looking for the next stage, my next stopping place. I find that using this method I am already familiar with the place when I reach it, making it less 'alien' and easier to reach. Trust me it works a treat and so far has helped get me so much further out there. If anyone gives it a try I'd be delighted to hear of their success. Stay positive.