West along Euston Rd, veer left at Old Marylebone Rd, continue along Sussex Gardens, turn left right at the end and then right to get onto Bayswater Rd (north of Hyde Park), continue along this heading through Sepherds Bush (right then left around the green to continue on Uxbridge Road for 10k though Acton. When you get to Ealing go passed the North Star pub on the left and take the right-hand turn only lane opposite M&S. Go along there passing The Haven pub and turn left at the end riding up Castlebar Road. Continue right to the top then turn right onto Mount Ave and immediately left onto Queens Walk. You'll hit Pitshanger Lane now.
http://maps.google.co.uk/maps?f=d&source=s_d&saddr=regents+park&daddr=Palace+Gardens+Terrace%2FA4204+to:51.507033,-0.249081+to:Pitshanger+Ln,+London+W5,+United+Kingdom&hl=en&geocode=FT8wEgMd2sP9_yHVN1vKg5c5VQ%3BFeT3EQMd_gn9_w%3B%3BFVs7EgMdRDr7_yltDFJWZRJ2SDGh27GcIW2rPA&mra=dpe&mrcr=0&mrsp=2&sz=13&via=1,2&sll=51.516221,-0.253029&sspn=0.072854,0.154324&ie=UTF8&z=13
West along Euston Rd, veer left at Old Marylebone Rd, continue along Sussex Gardens, turn left right at the end and then right to get onto Bayswater Rd (north of Hyde Park), continue along this heading through Sepherds Bush (right then left around the green to continue on Uxbridge Road for 10k though Acton. When you get to Ealing go passed the North Star pub on the left and take the right-hand turn only lane opposite M&S. Go along there passing The Haven pub and turn left at the end riding up Castlebar Road. Continue right to the top then turn right onto Mount Ave and immediately left onto Queens Walk. You'll hit Pitshanger Lane now.