Service taxis. In Jerusalem, they collect passengers at the Zion square, on the intersection of HaRav Kuk and Yafo, unless something changed in the last few years. The price is about the same as bus fare, but keep in mind they don't have a fixed schedule - they leave after they fill up, which takes 5-30 minutes of waiting depending on time of day and luck.

There used to be service taxis running from Hadar in Haifa to Tel Aviv throughout Saturday, and I suppose they're still doing so but I haven't had the chance to use them in quite a few years. This page has the phone number of the taxi company to inquire and get details (Moniyot Amal).

Note that if you're coming by bus or service taxi, it might make sense to exit at the Azrieli center, and from there it's about a 12 minutes walk to the cafe (the cafe faces Shaul HaMelech rather than Ibn Gvirol but the directions are otherwise good).