Many people find Cambridge places difficult to ring. Although in theory they are easy as you never have to go far, it can take quite a lot of practice to see the bells that you are working with. There are several different situations that you will encounter other bells during the places:
There are some other ways of practising the places, without having to ring the whole plain course. Note that the first two methods are false.
Places up - ring the 3rd in this method, which makes continuous places up (red line). But note that not all the dodges are with the treble.
Places down - ring the 4th in this method, which makes continuous places up (red line). But note that not all the dodges are with the treble.
Double Oxford - this has the advantage of being a plain method, so the plain course is shorter than Cambridge. You only ever do half the places, though (as in Yorkshire Major), and again, the dodging isn't with the treble. The treble is now the bell that comes through in the middle of the places.