Check the elevation of each point to ensure you keep enough clearance with ground.
What about determining how fast the AC can climb over an obstacle?
I plan to do the following kind of mission next summer: waypoints #1 and #2 at 2 meters above a lake going Litchi's max 54 km/h towards the 40m tall trees at the shore. Waypoint #3 on top of the trees 50m high still going 54 km/h. ...how much distance should there be between waypoints #2 - #3 so the AC has enough time to climb to 50m and not hit the trees??
I.e. how fast can Litchi make the AC go up while going full speed ahead? Can this be calculated in advance (not going to try this on a windy day...)? Maybe it is best to test this empirically with plenty of safety margin first, then fine-tune the mission.