On the road planning. Internet, Overnight parking, ...

I have the Allstays Membership and have it bookmarked in my browser on my laptop. It has most of what you are looking for: Walmarts, propane sellers, fuel stops, campgrounds, Rest Stops, RV dumps. The maps are also available in a download format so that you can view them without the internet.
I will continue the membership when it comes up for renewal. It is the first resource that I look at when I am planning a trip!