Leaving Concord we went out on the Strawberry Hill Road, Pope Road, South Street routing. Then there is a random left turn off of South Street, and the big climb was there. I have mile 24 on the GPS track right in the middle of it. This looks like "Heald Rd" end-to-end from South Street to Acton Street. (I should adjust the "slope" colors in the script, right now it comes up as a pale purple for me and that was actually pretty harsh.)