This route takes the path-of-least-resistance around Lake Union. A few points on the map wouldn't follow exactly the route I was trying to enter, but this is very close, will work, and you'll be able to find more direct paths in these few cases. ( For example, the southwestern "corner" of the lake can be hugged. )
There is very little elevation change during this route. The University Bridge is a slight climb, and you get a free descent after crossing the Fremont Bridge. The "trail" really does hug the lake and avoid Eastlake when given the chance, specifically to take an easier climb and give the rider a few level blocks to 'rest' between ascents.
This ride will take less than half an hour if you maintain a good pace.