Internet on the road
The only wireless method that I know of that is being used by RVers is to get a sattelite system for the TV and the modum. The catch is that the cost for the modum alone is $70 per month. We are fulltimers too and we just don't have the budget for that. What we do is to use a Pocketmail for constant e-mail when we travel and then when we sit for a time we use the internet provider. We have usually had Prodigy, who have local numbers in all major cities and most rural areas. When we stop for a month or more and there is no local number from Prodigy, we have them suspend our service until we go where they do have a number. These times we use some local provider for service.
Of course, you will not always have phones available in the RV. We spend about 60% of our time as volunteers in public parks and such and often do have access to a phone line. When traveling we find that most RV parks now have at least a line for e-mail use.