That is different from coat-tails crossing state lines. Show me the evidence that a presidential candidate's performance in Ohio has any bearing on congressional races in New York. The congressional races in New York could be impacted by the presidential race in New York, but not Ohio.
No, it's not. That popular presidential candidates gain seats for the party nationwide (and unpopular presidential candidates lose seats for the party nationwide) indicates that a candidate's overall performance affects congressional (and mayoral & gubernatorial) races across the whole country.
As Ohio is a key battleground state that gets the attention of all voters, then the presidential race in Ohio can reasonably affect the congressional, mayoral, and / or gubernatorial races in NY, NH, KY, MO, MI, MA, etc.
The main point stands -- Kasich's refusal to help Trump is harmful to the Republicans across the whole nation.