[nq:1]Where are you going or: where are you going *to* or even: To where are you going?[/nq]
The 1st or, less often, the 2nd.
[nq:1]I'll stay here or: I'll stay *in* here?[/nq]
The 1st
[nq:1]I'll go home but I'll stay *at* home, right?[/nq]
Right, but "I'll stay home" is also possible, as is "I'll stay in."
Adrian