youll know about the road maps once you open the destroyer, they're awesome!! i definitely do not recommend buying the odyssey book for the DAT, that is more for people taking the ACS exam, we don't need to go as in-depth as that. i only used destroyer for orgo and got a 20, which i thought i could have done better so using more sources definitely can't hurt you. there is no harm in being over-prepared.
i have heard good things about the hyperlearning so try that out too.