I know I'm a bit late to this party, but as a new shine runner myself, I've come up with a couple tricks to make the job a whole lot easier:
1) kill revenue men on the map... apparently, these encounters will increase the laziness of the revenue men's recruits... if you do this, stop at the check point, and wait. and wait... and eventually he gets bored and lets you go... you got about a 50-50 that they stop the wagon, and another 33-33-33 chance that if they stop you, they ignore you and let you go, they take 1 bottle, or they start shooting. if you do not stop if they say to stop, they WILL shoot, and they aim not for you, but for the wagons horse (or the wagon if it's in the way) which is costly
2) poisoning rival stills reduces the shine cost of the next batch to 30 AND speeds it up. Either via Maggie's quest, or finding one in free roam. blowing it up reduces the cost by 10.
3) Autopathing is your friend! if you play on PS4, hold down the touchpad till it goes into cinnematic mode and just spam (x). your wagon will follow the road flawlessly, avoiding all bumps and ruts in the roads. just be sure to exit cinnematic if you approach revenue blockades or your destination, as your wagon doesn't make that final turn off the road, but pulls over on the road.
4) last bit of advice applies to all wagons, and it took me a (long and frustrating) while to figure out... R1 is the break, but its also the button that, when stopped, you can hold down to back the wagon up.
5) bring a friend... driving is hard when you also gotta shoot n defend your wagon. therefore, bring a friend with you and they'll earn some money too. one of you shoots, the other can then focus on steering the wagon away from all those nasty bumps and rocks that break your shine bottles. square button tosses the reins to your friend, so if you need someone else to drive (afterall, a shine runner's gotta make sure the product they sells good quality) having a friend along also deters some solo griefers, causing them to steer towards lonelier prey.