+1 for Kennington. It’s same direction via cross passages, but they’re relatively short and quite wide so should allow you to see both sides. Camden Town has two platforms per northern branch and is significantly further apart due to the V-shaped layout, so won’t assist you with seeing everything.
As always I would recommend letting station staff know your intentions if you’re going to be there for more than a few minutes. They may, of course, not allow you to ‘loiter’, but equally it is far better that they know about you and your reasons for hanging around, as it can be very easy to mistake such actions for something else on CCTV.