score:3
As a general rule: If you can get there by bus, you can get there by car. There are of course cases where there are restrictions regarding private cars, but that's not the case for the places you're asking about.
Steinsdalsfossen og VΓΈringsfossen are both on FV-7. Have a look at route plan in Google Maps to see how to get there.
Folgefonna is large, and there are many different places you can visit. If you want to start at the summer ski center, it will take you 2 h 45 min.