Considerations for Long Rides
Maps: Most modern mapping receivers have enough memory to hold all the maps for a cross-continental ride on a removable memory card. However, some maps come in large chunks that may not fit. Consider loading up two memory cards and swapping mid-way.
Waypoints and routes: Most receivers cannot hold the 2000 to 3000 waypoints needed for a transcontinental ride. Swapping memory cards does not work for most, which hold routes and waypoints in a separate non-removable memory.
Create several files, allowing plenty of overlap, and reload the receiver along the way. One or two reloads should suffice. If you will not be carrying a computer or a PDA, you can put the files on a CD or a memory stick (flash drive) along with a small program like G7ToWin, which runs directly from your device without installation on a Windows computer. Beg a few minutes on a computer from a friendly local cyclist, a bike shop, or a computer shop. Most libraries will not let you connect your own devices for security reasons, probably a good policy. Do not forget to carry a short USB cable.
Power: Receivers with removable, rechargeable batteries are popular for long rides. Most use two AA cells, which run for about 12 hours. Some riders advocate one spare set and a solar charger. Some prefer to carry eight rechargeable cells and a small mains charger, needing a power outlet once a week or so and claiming less cost, less weight, and better reliability.
You can also buy single-use AA cells as you go, at somewhat higher expense and the need to dispose of them. Alkaline AA cells are good for about 12 hours in most receivers, while lithium cells last longer.
Most states in the U.S. follow the United States Resource Conservation and Recovery Act, which classifies the common alkaline, NiMH, and lithium batteries as non-hazardous waste. They can go into regular trash. However, California considers all batteries of any type to be hazardous waste, which must be taken to a recycling center, a household hazardous waste disposal facility, or a universal waste handler. Find out about other states and countries with an Internet search.