The clinic would probably be for Helena, the "interior decorator" is Eva, both still active (even if there was a big pause for Helena). No idea who the driver is though. There's Rose as a rigger, but she didn't go on a road trip so...
As for the links to the larger plot, there are some between a bunch of characters, at least through some NPCs if not the plot itself (visibly anyway). The two for whom I don't see much are Grunt, Helena and Lizzie. For Lizzie, there is a start, but it's not much and nothing direct. For Grunt, and Helena nothing for now as far as I see it (both were bombed, so there's definitely something, but nothing visible).
Last I heard, the links (at least in duos) was schedule for soon™. Cynthia is probably in good position to link (or at least interact) with a bunch of characters. With Preston through Tanya, with Spokane given his last activities, Eva she already knows (even if she doesn't want to have anything to do with her ^^). Johnny is digging into the same things she is but from a different angle probably, so possible but not that easy for now (and he just started, so it might be too soon to link). Others like Grunt and Annex for example would probably link easily with pretty much anyone, no idea about Helena though.
For others linking with other characters won't be easy. I'm mainly thinking about Lizzie and especially Eva.
As for Preston, through Tanya there are Rose and Cynthia, Annex and Eva but it's more indirect (it would be through Ni Ni Xiaoliu, one a Tanya's contacts), so the possibilities exist ^^ Of course, since all of those are at least almost three days after Preston, it's not easy...
