Where do you begin to learn playing phrases in triplets over a bass that is in straight eighths etc..

Am I missing something here or is this hard to accomplish?

I'm struggling with counting this or even visualizing where the bass notes fall?

Agree with the above.
For me I think of "Hot Cup of Tea" (i'm a Brit!)

Hot = both hands - quarter note
Cup = the hand that is part of the 3 - eighth note
of = the hand that is part of the 2 - eighth note
Tea = the hand that is part of the 3 again - quarter note

I read on a recent thread about hand independence actually being either both hands playing a note together or some rhythm combination between the two hands. That is the perfect approach, not thinking of it as hands working independently from each other. By thinking of a single rhythm that combines both hands playing simultaneously OR alternating in a determined rhythm one can get the 'independence' sound.
We use the term independence but in reality the hands work as one to create a rhythm so by strictly hands do not work 'independently'

Attached is a little pdf worksheet I have my students use to help them manipulate different meter groupings. It would work great on a stick....
It has 3v4, 4v3, 5v4, 5v3, 7v3, 7v4

I read on a recent thread about hand independence actually being either both hands playing a note together or some rhythm combination between the two hands. That is the perfect approach, not thinking of it as hands working independently from each other. By thinking of a single rhythm that combines both hands playing simultaneously OR alternating in a determined rhythm one can get the 'independence' sound.
We use the term independence but in reality the hands work as one to create a rhythm so by strictly hands do not work 'independently'