Correct. There is no "plumbing" in the car to get access to the battery's DC connections. This is the same whether the original or "3.0" battery. Tony's adapter is essentially a large relay that gets inserted between the motor and PEM (I think), along with the requisite plumbing to an external connector, and some clever logic that makes the car think it's in Regen.If I read correct, the Roadster can not use the quick chargers unless you have the CHAdeMO system installed? Is that right?
The reports are that it works rather well, though there are some small side effects. The install is also rather intrusive, though not irreversible. I think he's done a very good job at engineering it. If I had a larger need for it I would go for it, but faster charging not that critical for me right now. As you are doing, consider the availability of CHAdeMO chargers along your routes. For me, the ones I would use tend to be reported as broken on PlugShare more often than not, so I can't rely on them, and there's a Tesla Service Center along the way with a pair of 80 amp HPWC chargers that they let me use if I ask nicely. (The sales team loves having a Roadster sitting just outside the main doorway!)