Seeing as she plays the Cello &/or violin in most tracks on Driftwood I don't think you can say that Rena Jones has no strings at all. I must admit though that when I first heard the album they passed me by but when I really listened to it there they were, plain as day.
I don't think strings is what you are looking for as I don't hear any strings in Cloud Kingdom, there is a high pitched synth melody that is what I think you like if so try looking at a lot of oldschool ambient like Future Sound Of Ambient I & II especially Intermix - Solar Temple or Future Sound Of Ambient III & IV especially Man With No Name - Azymuth