What does the map scale mean?
One way of explaining the scale is say for a 1:25 000 map, one unit on the map, whether centimetres or inches, is 25 000 times bigger in real life on the ground. So of example if a road is 1cm on the map at 1:25 000 scale, in real life the road is 25 000 centimetres long or 250 metres or ¼ Km.
What is the difference between a Small Scale and a Large Scale maps.
The difference between a small scale and a large map can be confusing. A small scale map is something like a road atlas or road map at a scale of something like 1:250 000. It is a map that covers a large area, but in less detail. Whereas a large scale map is a map that covers a smaller area in more detail, these are generally the walking and cycling maps at 1:25 000 or 1:50 000 scales. Any scales above these two will not generally have sufficient detail for walking, the 1:25 000 being the best scale.
For a given map size, a large scale map covers a smaller area of ground and conversely the smaller scale map covers a larger area of ground. Another way of remembering it is, the larger the scale number, the less detail the map. So a 1:500 000 scale map will have far less detail than say a 1:75 000 scale map.
The best maps for walking.
The best generally available maps for walking are the 1:25 000 scale, although you could use the 1:50 000, but they would have less detail than the 1:25 000 maps. However, some countries do not have maps at this scale and you may have no alternative but to use 1:50 000 or 1:75 000 scales.
The best maps for cycling.
The best maps for cycling are probably the 1:50 000 maps, but if you need to plan your route over a larger area, you map also need a 1:100 000 or 1:125 000 map.
The best maps for driving.
The best maps for driving are going to be from 1:250 000 to 1:500 000 scales. Folded maps are obviously useful for this if you wish to open it out to plan a route. Otherwise an atlas is going to be the next best thing. Atlases that are spiral bound will lay flat easily in the car, but they do tend to fall apart more quickly with use than a paperback or hardback atlas. The main problem with a paperback or hardback atlas is that they will not always lay flat on the car seat. You end up having to keep finding your page.