Well, here's a summary of the routing providers off the top of my head.

• MapQuest Open: probably a deprecated service after MapQuest's revamp a while back: "They are currently still maintained but their future is still being determined. Sorry, not much more news than that at this time."
• OSRM: Demo server is very unstable, not usable in production even for a small user base.
• Mapbox: Impossible terms unless paying $500/mo.
• HERE: Impossible terms.
• GraphHopper: The last I looked, they had good routing, but really bad turn-by-turn directions. Will need to recheck this.

So, there might be need to set up a server, but no hurry while MapQuest Open works. And, of course for the current user base who install their own phone OS, running OSM Scout isn't unreasonable either, even though I prefer the ease of online.