You can cut down on your connection costs by installing a navigation and off-line mapping application such as mapsme or osmand. Both are free and you download just the maps you need. Many Overlanders use these apps exclusively for their travels all over the world and they use the smart phone gps for position info.
On osmand you can set it to record and display your track so as you walk around a city you retain awareness of where you have been. Takes a while to get fully into its capabilities though.
BTW now you can also install ioverlander and get right into the 21st century. You can even post all the rv parks that ioverlander doesn't yet have - with photos too.