Mice love to have lots of toys around. All kinds of tubes and ladders are very popular among mice. Ordinary toilet paper rolls are more than suitable for mice. Biscuit and other small cardboard boxes are very suitable for mouse toys. You can attach several small boxes together and hide them under the beddings. Don't use glue, adhesive tape or metal to attach the boxes together, your mouse might hurt itself. Just make a hole on the side of the box and stick a slightly smaller box a bit through that hole to attach the boxes together. Mice will also chew on the boxes and make more and more little doors in them until the whole box is one big hole! Always remember to remove all plastic parts from the boxes.
Ladders can be bought ready made or you can make them yourself. Non poisonous branch of tree (willow, for example) from unpolluted area is also a nice toy to climb on.
That mousy smell (and mice do smell, at least to a non mouse fan's nose) can be diminished by giving the mouse / mice glass jars. Take a jar, jam jar for example and wash it thoroughly. Place the jar on one side and put a little amount of bedding in it. Mice use this kind of glass jar as a toilet. The jar is very easy to clean up daily. Mice can also learn to use a litter box, that is a small box with kitty litter in.