I think an iPad with 4G cellular is the best thing to come along since sliced bread for RVing.
Use it in the passenger seat driving down the highway to check traffic backups ahead, find alternate routes when the Interstate closes down, check fuel prices with the free GasBuddy app, find campgrounds, look at attractions we might want to see. Send and receive messages.
And of course, driver can use after pulling in for the night. Aside from initial iPad cost, we pay $25 month to month to AT&T.
We have the cheapest possible phones, not Smartphones, don't miss them.
Have considered adding a (pricey!) Surface Pro since the old Windows laptop is aging out. (The only reason we still bring along an old laptop is work-related on long trips, to download full resolution photos off the memory cards from our cameras and burn DVDs as backups.)