You folks that don't think you need a fast Internet connection to use the Internet for "only simple browsing" need to try out the boondocking (or certain other) section(s) of these very forums.
Certain of these topic areas contain a lot of photos. You can hardly get around to enjoying these with a sluggish connection. By the way, I can't even get into my banks with sluggish connections.
For unlimited hotspot 3G/4G service, sign up with these guys on the Unlimited Plan. I believe they have a way for you to turn it on or off to use just for RV trips too ... so you don't have to pay the fee every month even when you are not using your RV:
http://millenicom.com/