I just saw a post about vehicles, and these came to my mind.
First, and maybe easiest one would (and surely be) be a horse, though it would have a lot of cons, such as being shot in a second, needs breeding, you need to keep him alive, but it is good for long distances in the non-dangerous zone.
Horses may pull a 4 wheeled cart, which might be way more slower (though still paying off), but here comes the fun part: what about customizable ones? You start by a single wooden cart, which you can armor at its side first so it will be good as barricade upon being attacked. Then you can make it a closed one, with shooting holes/windowses (for balance maybe). Closed carts can also be armored (as long as they arent, you will be hit by bullets). These carts will have the ability, to build a door on their back crafted, and working as all the other doors do ingame. You may place anything on the cart, like boxes, sleeping bags etc… Excellent for nomads, attackers, and lonewolves.
Then there would be its faster type, the chariot. It would also have an armored version, but thats it. Horse-only aiming is shit, so you may want that (and the cart).
The next vehicle would be a crafted mower-engine gokart. Why gokart? Cause it would be balanced to cost, so moving on road would give a good speed, while those wheels would struggle on other surfaces (If you want to make it fun, make it so it really removes grass like a footprint). rocky road<dirt road<asphalt<grass<snow/sand.
The least interesting one would be a dune buggy, though could also be customizable. It would cost in c4 heights.