There's a new RV-specific navigation app available called SmartRVRoute 2. This is actually the second generation of the previous app. The developer of the app is Teletype which is a pretty well-known name in semi truck navigation. They have a very similar app for trucks as well.
It's available for Android and iPhone. The Android link is: https://play.google.com/store/apps/details?id=com.teletype.smartrvroute4 but I'm not if the new version is available for iPhone yet. The Android version runs on both smartphones and tablets.
The app is built over the top of Google Maps and it is an online solution so you must have a data connection. The obvious advantage of building over Google Maps is that the map is very up-to-date. Basically, when Google Maps adds a road it will be added in this app.
The route is calculated on the developer's servers because the developer builds RV specific route restrictions as an added layer on Google Maps. You enter the specifics of your RV dimensions and weight and the server understands relevant road restrictions and builds a route around them.
The app also helps with propane restricted tunnels but they do this by using the DOT Hazmat rating system in the RV settings. I don't think the Hazmat ratings really apply to RVs but I think by selecting Hazmat rating 2 it should pretty much achieve the results of avoiding propane restricted tunnels.
A downside to the app is that while it shows Google traffic it does not take Google traffic into account when calculating ETA or selecting the route. It does use historical traffic by time of day to calculate the route though. I've found my test route ETAs to be really accurate. You can manually avoid incidents and you can manually avoid an area but traffic is not avoided automatically.
You can build up to 10 via points or stop over points in a route. Unfortunately there is no way to build this in advance, save it and then activate it at a later time. They claim to be working on that functionality. They do have a web-based route planner that can then send the route to the software but I have not tried that.
The servers also build a layer of RV specific POIs over the top of Google Maps and displays them with large icons on the map. These include a very robust database of truck stops and the icons shown on the map are branded. It includes campgrounds, truck washes, rest areas, etc. You can press on any of these icons on the map and immediately generate a route to that location or add it to your trip as a via point.
The app is an annual $59 subscription fee but they also have one month and 3 year subscription options. Every day at 1 p.m. EST the full functionality of the app is available for free for trial for an hour. Outside of that time window, without a subscription, you can fully explore the app and the settings and the map but you cannot calculate a route.
2011 Born Free 22' Class C Rear Side Kitchen