Hey Yogi, Reefer pays a bit more because of the responsibility you have with perishable food items plus the responsibility of the engine that runs the reefer unit. You would need a bit more training upon being assigned to the reefer division.
Different products require different temperature settings, and some are very delicate, such as lettuce. Lettuce loads require a setting of 33, which is just a degree up from freezing.
CDL training is really your decision. At the trucking company, you won't have to front any money as opposed to a 3rd party school where you will have to pay.
Dedicated routes are a route that you deliver to the same consignee every time. Sometimes you may even pick-up at the same shipper every time.
And GPS systems are a ways off from being foolproof for trucks. But, I'm old school and would rather depend on a map/shipper-consignee directions than a GPS system. Jimmy