Hi All, Happy New Year

I was wondering if anyone could suggest the best way to research this conundrum:
1851 - the census has Sarah SMITHERS, Daughter of Robert SMITHERS & Caroline ARTERS, born 1846 in Oxshott Surrey, listed in the house of Charles DODSON & Jane (late RAFFELL) as COUSIN, in Thames Ditton, Surrey. Charles was born Hampton Wick in 1825ish and Jane in Oxshott, abt 1824.
I have researched quite a bit of the tree for Sarah SMITHERS as she was my 2nd Great Grandmother, but have no link to either the DODSON family or the RAFFELL family so far.
Sarah's Grandparents were John ARTERS & Sarah SPICER, and Thomas SMITHERS & Grace (Unknown)
Any ideas on how I can find out if they were related or not would be very much appreciated. If they were not related why would she have been with them several villages awayfrom her family?
Regards
Pauline