I have the same experience. My routes are planned by Strava (premium), GPX is exported and imported in Garmin Connect. You can only switch off Turn Prompts completely on the 130, there is no "Prompt on demand" option.
I plan my courses (routes) using RideWithGPS Premium which has an excellent (IMHO) planner. It also has a very useful 'Review Cues' facility for checking, changing, deleting or adding new cues to the route. The same edits can also be done manually.