As a Ride Captain for a group of approximately 30 riders I have a fair amount of experience in creating routes and have complete trips for up to 14 days both with the 14-18 Boom System and now the new in the 19's. I cannot speak to the Harley Ride App as HD has not seen fit to have it work or even in the app store outside of the US. Anyhow, here is my recommendations and cautions. I do use the HD Ride Planner and since they updated it, I find it works quite well.
First, I highly recommend you load your routes on a memory stick. I recommend at least a 16mb stick.
Next, a word of warning! Just because the routes showed up with the ride title in the Boom Box (loading all of them at once) does not mean the available memory in the Boom Box was capable of downloading your routes in their entirety. I learned the hard way and upon selecting a day 3 route the entire system froze and there was not a thing I could do about it. I pulled main fuse etc and natta. Upon finally getting to a dealer, they had to wipe the entire system and reload it. Lesson learned! I now have all my routes on the stick and download them on a daily basis while erasing the previous days. I now have the GTS on my 19 but still do this. It only takes a few minutes to load a route. If the app allows you to do a similar method, that is my suggestion.
Lastly, waypoints, waypoints, waypoints. Can't be any clearer. If you have any expectation of the bike gps following the route you plotted on your computer you cannot use enough waypoints. I place a waypoint just past every turn on my routes. You must also take the time when plotting to zoom in and ensure you are putting the waypoint actually on the road. Again lesson learned, that my waypoint was in a field with the cattle because under normal view on the ride planner it looked on the road but when zoomed in it was off the road. Waypoints use memory in the GPS and thus another reason I download daily.
My settings are generally, avoid highways (if you do have a highway plotted on your route it will still follow it. Waypoints!), fastest, avoid gravel roads. The rest of them are up to you but most of the settings are there for the person who just puts in an address and wants the bike to take them there so you are telling the GPS when it is internally building the route what to avoid. If you are building an entire route with lots and lots of waypoints these avoidances really don't come into play. I will even throw a waypoint in every 20 miles or so on a road you are going to be travelling for a long distance. This forces the GPS to follow "your" route not its.
Hope this helped, and good luck!