Are you familiar with A better route planner? I recommend checking that out, I think you will be surprised just how far you can go.
If you are really concerned about if you will make it you can get a phone app called Power Cruise control and a OBD II dongle, I have this but only use it when I am pushing it in my plus or must want to play with it. This is like abetterouteplanner but it is real time showing you are using too much energy like your driving style or heater or whatever to make it to your destination. Most people do not need this only but it interesting when you are driving some hundreds of miles.
Colorado is much improved even over the last year, you can often find an l2 if not a DCFC, don't forget RV outlets as well. I charged while camping at Ridgway state park for example (the town does have an L2 but camping is more convenient). Now we have a fast charger in Montrose so things keep getting better.
Wyoming is a whole different pain in the rear but I do know a guy in a 40kw LEAF who drove from here to South Dakota and back it just took a long time finding outlets and such.