My suggestions for cargo types and load/unload points:
Loads:
-Sport cars
-Cars
-Used cars
-Wrecked cars
-Securicars
-Sedans
-Vans
-Special vehicles
-Antique cars
-Lowriders
-Tractors
-Police cars
Loading/unloading points:
-Every single pay 'n' spray
-Every single tuning shop
-Every single car dealership
-Every single junkyard (wrecked cars only)
-Warehouses
-Screwy's garage
-SF load/unload point exactly like singleplayer export dropout, at thief unload spot
-Any expensive house (supercars only)
-A couple of Casino/hotels in LV (supercars only)
-LV yellow bell station
-Bone county Octane springs train station
-LS Unity Station
-Farms (tractors vans special vehicles only)
-Docks
-Airports (special vehicles and vans only)
-Lv and Ls racetracks (sport cars and special vehicles only)
-Banks (securicars only)
-Area 69 and army bases (vans and special vehicles)
-Fire stations (vans and special vehicles)
-Construction sites (vans and special vehicles)
-Quarry (vans and special vehicles)
-SF and LV golf courses (vans/special vehicles)
-Police stations (police cars)
-Oil rigs and refineries (vans/special vehicles)
Loads:
-Sport cars
-Cars
-Used cars
-Wrecked cars
-Securicars
-Sedans
-Vans
-Special vehicles
-Antique cars
-Lowriders
-Tractors
-Police cars
Loading/unloading points:
-Every single pay 'n' spray
-Every single tuning shop
-Every single car dealership
-Every single junkyard (wrecked cars only)
-Warehouses
-Screwy's garage
-SF load/unload point exactly like singleplayer export dropout, at thief unload spot
-Any expensive house (supercars only)
-A couple of Casino/hotels in LV (supercars only)
-LV yellow bell station
-Bone county Octane springs train station
-LS Unity Station
-Farms (tractors vans special vehicles only)
-Docks
-Airports (special vehicles and vans only)
-Lv and Ls racetracks (sport cars and special vehicles only)
-Banks (securicars only)
-Area 69 and army bases (vans and special vehicles)
-Fire stations (vans and special vehicles)
-Construction sites (vans and special vehicles)
-Quarry (vans and special vehicles)
-SF and LV golf courses (vans/special vehicles)
-Police stations (police cars)
-Oil rigs and refineries (vans/special vehicles)