If our present suffering is the result of bad karma from a prior life, what is the real present remedy for suffering in this life? Can all suffering be alleviated in this life through our efforts with the Eight Fold Path? Why engage in any effort related to the Eight Fold Path, if the only true benefits are to be realized in the next life?
Can all suffering be alleviated in this life through our efforts with the Eight Fold Path? 


Yes. That's the promise


  Why engage in any effort related to the Eight Fold Path, if the only true benefits are to be realized in the next life?


This is a misunderstanding. True benefits are realized now. At the present moment. Anyone who wait for next life or even tomorrow are simply in a state of suffering.


  If our present suffering is the result of bad karma from a prior life, what is the real present remedy for suffering in this life?


Non of your suffering is based on bad karma. Suffering is something you do. Not something that happen to you. Enlightened person realize this and stop doing it. 

You may have a back pain, which may or may not be karma from past life. But you don't have to suffer it.