A couple things occur to me.
First, do you use a double-blade paddle? If you do, a trolley probably won’t be seriously in the way of your paddling. If you are a single-blader, I think you might regret having such clutter alongside the hull.
As to the need for a trolley, I tend to think that’s a complex solution to a very simple problem. Like BigSpencer, I usually find it perfectly adequate to drop an anchor over the side and tie it off either to the thwart in front of me, the thwart behind me, or even the seat frame, depending on how I want my boat to “hang” in the wind or current. If I really needed the anchor to attach to one end of the boat or the other, it would be fairly simple to rig a line that’s long enough to reach from the end of the boat to where you are seated that has a metal loop or carabiner on the end, plus a length of additional line (or continuation of the main line) that you can tie off near you to keep it within reach. This way you could tie off your anchor line to that metal loop and toss the whole works overboard, and then your anchor line is effectively attached to the end of the boat. When you need to pull the anchor in again or change the length of the anchor line, you just grab that extra length of line that’s nearby and pull the metal loop or carabiner right to your lap and make whatever adjustment, connection or disconnection of the main anchor line that is needed. It will be less noisy than a set of pulleys, and can be removed or re-installed as fast as you can untie or tie two knots.
For a canoe, I use very small-diameter anchor line, about 1/4-inch, which makes tying knots a breeze. Cleats would be even easier, but if you do tie knots, simply make the knot “on a bight” rather than using the actual free end of the rope, as that’s just about as fast as using a cleat.
Another trick is to cut a piece of very light plywood for wrapping your anchor line onto. I cut a piece that’s about 12 to 14 inches long, 4 to 6 inches wide, with a wide “U”-shaped notch cut in each end. Wind the rope onto it by hand. This is handier and quicker for winding up or winding out anchor rope than any fancy crank system you can buy and attach to your boat.
Some of this is more than you asked for, but appropriate to go along with my other thoughts on anchoring.