Everyone had to start somewhere, usually not where they wanted
The first year ya gotta pay some dues, only you can decide what trade offs you're willing to make.
The haz-mat test isn't really that difficult, but you do have to study the manual to prepare. I would do it if you don't have a "dis qualifier" in your history. Enough drivers are not willing or not able to maintain the endorsement, it may work to your advantage. Doubles, triples, tanks and hazmat, I've used all of them, some more than others, but there are more options.
As to the mountain driving, I agree if it's not comfortable I'd go slow. But at some point you'll need to take the plunge. Just keep it in a really low gear and go super slow, people will pass and you'll gain confidence. Never let your confidence fool you....... out in the west it's Eisenhower, the Grapevine, Ashland and Cabbage....... let the supertruckers pass you.
BOL