Hey, I did Eng Lang by distance ed last year (without having studied units 1&2) because my school didn't offer it.
Your experience could be very different to mine but I hope this gives you more information about how things *could* be for you.
I suspected this was going to be a challenge so over the holidays I taught myself all of the metalanguage and read through textbooks and notes. The class content was interesting and easy to understand, and we would even sometimes have online classes together. We also met up in person to have a "real" classroom for a day. The problem however, was that I didn't know how to improve Feedback was given significantly later than the online work indicated; for example, we might be told to prepare for the upcoming SAC by revising our feedback on the week __ analytical commentary, but we didn't get any feedback on ACs until after we had to write one during that SAC. When the feedback came it was a rubric, a few notations & a paragraph at the end, but I still often felt that I didn't understand where much of my marks had come from or how to change them. Maybe I could have changed this by being more proactive with sending emails and asking for additional feedback - I'm not sure. On the plus side, the teacher I had was very experienced, enthusiastic about the subject, and wanted to help us succeed; I suspect that if the student:teacher ratio was different that the experience would have been a more rewarding one and a less stressful one.
In short, if you do choose distance ed, you should probably get a tutor to give you essay and analytical commentary feedback
I hope this helps