Allow a trailer to be attached to the steam truck and gasoline truck. It will allow for a large amount of extra storage, but drastically slower speed, higher fuel consumption and the vehicle should be immobile if driven offroad (non stamped dirt, asphalt or concrete).

The mechanics crane has very very limited usage. If you allow the crane the have a function to pickup blocks. Reworking this crane to be used on a trailer behind a truck, it would be a very useful vehicle for road work. Replacing dirt/stone roads with the crane would be a big improvement, as well as a bit more fun than the current tedious road work.

Other trailers could be for example

cold storage; To transport food/crops.

animal carrier; To transport animals once husbandry gets added

log carrier; If a trailer can only be used specifically for logs, allow it to store more than the regular storage trailer.

Mining equipment, move mining related worktables between mines. Its common to travel to different biomes as a miner, being able to bring some of the machinery with me is both realistic and useful.

The options are endless. But having the option to attach a trailer in exchange for speed would be beneficial. Transporting goods is a large part of the game and with the addition of boats, I feel we're headed in the right direction! Looking forward to the trains/minecarts :)