Yeah, it doesn't give enough information to give a solid answer.
Not enough information?
It doesn't say that the man
isn't travelling to St. Ives as well, and due to the ambiguity of "with" we don't know if these wives knives and hives are with him in a property relation, with him in the place of meeting, or with him on his journey to St. Ives. Cf,
That man over there
with seven wives (maybe not his wives, but they are present).
The man
with seven wives (his wives, maybe not with him here)
The man travelling
with seven wives (maybe not his wives, maybe not present, but they are travelling together).
When you read that deep into it, the riddle collapses under its lack of conciseness. But then so would most riddles, hence my not reading that deep into it initially and proposing the answer "none."