For general trip planning and execution, I use a combination of Google Maps, Plugshare, and EVTO-Tesla (all on my Android phone, or Google Maps on the PC pre-trip). Energy use prediction depends a lot on terrain, weather, and how you drive, so it will take some experience to get the best predictions. Since this is your first big trip in the car, be conservative in your planning (try to stay above 30 miles or so), and include alternate charging sites in the inevitable case that at least one of the planned stops will be out of order, fully used, or "ICE'd" (blocked by a gas car).
After referencing Plugshare, you should take note of what company sponsors the various charging stations along your route. Some use a membership card for activating the station, and for billing if there is a charge. Visiting their website or calling the number will get you started with them.
I haven't experienced much in the way of trouble with either of Henry's CAN adapters, but some have reported that the newer Tesla Destination chargers may take 30 seconds or so to cycle through incompatible modes before finding one that works. So you may get a few errors before it actually starts charging. Also, at least one of the Clipper Creek chargers (HCS-40?) charge just fine, but then keep cycling short (several seconds) charging sessions forever after the primary charge is complete. This is hard on the battery and contactor, so don't leave them connected overnight. There are some older Siemens chargers that have been reported to be problematic, not working at all.
As DeedWest says, don't overlook the RV parks, but you will need the Mobile Connector (UMC) in order to access their 240 volt outlets. In any case, take your time and aim for destinations with charging for over night stays, leisurely meals, sight seeing, etc.
Good luck with your first Roadster adventure, and welcome to the Forum and the community!