Not to far off just have to control the carriage when you purchase them. It is discussed in the more recent series.

This doesn't work anymore as a carriage can only transport one type of goods.

You know for my USA series I may just go in and make those adjustments. I liked it before the changes. Not all cargo could go on all vehicles but at least the train cars kinda get it right. Have you messed with the actual cargo mod that adds households goods as the final product. I had fun with it in my Modded series. https://www.youtube.com/playlist?list=PL2NZzDrzXcUtCagDeF8iyI9UJ4dieUqXr

Indeed it really is a whole new game.

I did the following
What I learned from the real life is that 1850 horse wagons as well as all open-type wagons and trucks are freely used to load whatever cargo you need. Even oil can be loaded if supplied in canisters.
Obvious exceptions are tank-trucks and tank-wagons, forest trucks and wagons and possibly "goods" vehicles (closed secured cargohold).

From this logic I used developer-provided simple hint (patch 6219 Sept.19) to modify all the vehicles (except for passengers vehicles & trains itself) to accept multiple cargo types. It took me about 20 mins. to modify the files with Notepad.

It was fun while it lasted Sweennyy. In both the Modded series and Nordic DLC I make use of the new style each truck to its own cargo. The mod series is fun since I use the cargo mod that is a whole new game in my opinion.

In the latest patch you can't load the same truck with different cargo types.
This ruins the whole approach

Just finished the year 2000 and what a ride. Hope this helps those who have been commenting about struggles with Hard difficulty.

Just finished up the series and wanted to post this guide for those trying to knock it out on Hard Mode.