I have a train line: coal mine – iron mine – steel mill. I placed a truck stop at coal mine and set up a couple trucks to nearby city. Attached a goods wagon to trains. As a result trains will bring back a few goods that will move from train station to truck stop they pick it up and deliver it to the city. So in this example it looks like it works.
I think any combo like this should work on paper but depends if there is enough demand and if the complex route is still the best option, then it should work… save before, set up and test, trial and error I guess…