You can put-in on either side of the Rt 1 bridge in Rotary Park, and there are also additional options further down on river right.
On river left, to the right of the gazebo and sign, between two granite posts, are stairs down to the rivers edge. Eddies are lacking so it can be a bit sketchy at higher levels.
On river right, one can put on underneath the bridge from the front parking area of the gas station, or go further down Brown St, behind the Cumberland Farms and before the office building for Kennebunk Land Trust, to a dirt access road which leads to a myriad of put-in options for anyone wishing to avoid the initial drops.