Hello Rob and thank you for your encouraging words!
I checked the electric schematic of the SN65HVD230 based board you mentioned. It can work with the CAN library but in a direct mode. I mean, pin 8 (Rs) is been underused and fixed to ground (high-speed mode). The CAN library contains the SN65HVD234 component data conforming to Arduino API that will be sub-utilized too (I think you don't want to port the manufacture ones).
I would recommend it only for tests purposes, but for your application, you will surely want to migrate to 234 to take advantage of the Due libraries for ultra-low current sleep mode. Additionally, the missing filter and buffer capacitors should be needed if distance between Due and CAN device increases.
In case you decide to get it, I would also recommend to get two for loop tests of the CAN controllers. Notice that the manufacturer's (Wave Share) price differs considerably from the vendor's (DX) (Russian?). By the way, I don't see the 120 ohm terminal resistor in the photos. Only the 10K, I think. Regards!
Here the schematic of the SN65HVD230 based board you mentioned.