Coyotes and mountain lions… and bears? (oh my!)
Yeah, I've definitely heard of housecats and lap dogs getting swept up by coyotes -- chihuahuas, shih tzus, poms and various -poos. Coyotes themselves aren't that large, though. 30-40 pounds sounds about right. A basenji might be too big for a coyote, but I wouldn't put it past them to try (and do some serious damage in the process).
Mountain lions, on the other hand... the thought of them does make me nervous! There's a few heavily forested trails that I've taken my shiba to, but haven't been back since we got our basenji (she would definitely be on leash if we ever go). Every now and then I hear about mountain lions attacking joggers, but that's become more of a general caution than any citeable story now. The closest that any "scare" has come to me was my friend who regularly walks these trails said he was going for an early morning walk, saw a part of a deer leg along the path, and promptly turned back around.
nobarkus, you mentioned that you saw a coyote last time too. Just out of curiosity, what time of day do you go to this trail? Does it matter, with coyotes?