About 99.5% is on road. Only exceptions are 100 metres of park path on one of the routes, and 50 metres of pedestrian bridge on the other.

Occasionally I use MUPs for various errands, including work-related ones; in particular, there is a stretch of a Lakeshore MUP that is smooth, flat, straight (great sightlines), relatively deserted, right by a road (so access is not a problem), but with few enough intersections that stopping for them is not an annoyance. However, MUPs like that are impossible to build most places: you need just the right combination of factors that does not happen very often. So roads it is.