Surface travel is generally less fraught than air travel, but in some parts of the world can nevertheless be chaotic. Many of the principles advocated for air travel consequently still apply. Ensure you are well organized, minimize the number of separate items carried, travel as light as possible, and consider using bags on wheels.
Security of equipment on public buses, boats and trains can be a problem, particularly if you fall asleep or are not seated close to your baggage. There are all sorts of scams worldwide, mostly designed to distract your attention while a bag is stolen. Watch out for pickpockets during the journey, and guard your baggage when the vehicle stops. Departing passengers and opportunist thieves can remove items in a few seconds.
On long journeys, particularly in cars and buses, avoid placing your equipment and any film in local hot spots. These are found above a vehicle's engine, near sunny windows and in vehicles parked in direct sun. In dry conditions the worst hazard is dust. It seems to get in to everything. Cameras are particularly vulnerable when lenses are removed or backs are opened. On dirt roads, such as those found in Africa, and in windowless (colloquially "air-conditioned") buses, seal cameras and lenses in zip-locked plastic bags or put your whole camera bag into a disposable plastic sack. Similar precautions offer protection from spray and salt in small boats.