Hi
>> "mikaketa da to?"
"TO" and "DA TO"
"To" has several meanings. It is a kind of postposition or conjunction(= and).
When connecting "da" and "to" in the question, it means, someone is asking to confirm what you said.
In this case,"mikaketadato?", someone is asking to confirm whether you saw or not.
For example,
A: I saw him.
B: Did you just say "I saw him"?
In Japanese,
A:kare o mikakemashita = kare o mimashita = kare o mita
B1:(kare o) mikaketa da to? = mimashita da to? = mita da to?
B2:(kare o) mitan(o)desu ka?(natural and polite )
B3:(kare o) mita no? (spoken language but more natural)
These Japanese sentenses, B1 - B3 are basically the same meaning.
But B1, the sentense end in 'to' is usually used in written language and sounds little bit old fashioned.
>>sore ni sawaranai hou ga ii to mo yo. = "Sore ni sawaranai hou ga ii to omou yo"
It means,
"I think you shouldn't touch it."
In this case, "to "is postposition and usually put after noun or sentense
It is hard for me to explain in English. I hope you understand it^^