LineStyles: combining dotted and normal lines

Hi all... this is driving me crazy. I am currently working on pre WW2 topgraphic maps - converting them to an AI image. Working on the roads, I have a question on a line template I cannot figure out how to make - okay: I am a newbie @ illustrator but I've searched the web and still cannot find anything 😞 I'll literally walk you through it (see attached illustration). My starting position is on a big, good road (1). I use a line with offset. No problem and lines join beautifully. Then I move to a slightly smaller road, less broad (2). I use a singel line in the color or the 'offset lines' of road (1). No problem again. Just a single line. Done. Then I move on to the third road, even smaller (3). No problem either, because this is a transparent line with offset colored lines. Now here's the challenge: from this road (3) I walk into a forest where I have a road that is just earth (4). Not smaller per se, but no more hard surface to walk on. A full line + a dotted line. But how do I do that??? Parallels won't work, as they only work on shapes. I then could cut the base, but that would be a gazillion amount of work. And I see no way to use the offset lines trick to make one line full, while the other is dotted. HELP. 🙂 I am lost (so I won't even get to roads (5) and (6) that are no problem again, though they'll lead me farther into the forest 🙂 Well, thanks for your help - I cannot imagine that illistrator isnt up to this??? Stay safe & in good health! Wim