I have driven 149 from South Fork to Lake City and back several times but it has been several years. Slumgullion Pass just south of Lake City is an 11,500' pass. Pretty good highway (or at least used to be) with one tight switch back and some steep grades. But a really beautiful drive. If you have a diesel I don't think you would have a problem over it being very careful on the grades. And if you don't have a problem on high mountain roads and passes. Don't let the dangerous roads name in the link below scare you. I have seen worse. And Creede is worth a stop along the way.
https://www.dangerousroads.org/north...lion-pass.html