Is This Approach to Solving Wrench Reduction Correct?

[Saladsamurai]

This one is really discouraging me. It looks sooooo easy since the forces are each in one direction

The way I have usually handled these as a procedure is: Find $F_r$ and then find $M_r$ about some point and then decompose $M_r$ into components that run parellel and perpendicular to $F_r$. Then I can usually find P(x,y)

If I were to move everything to point A I would have:
$F_r=500i+300j+800k$
And I would also have to find the couple Moments about A:
$M_x_A=4(800)=3200$
$M_y_A=0$
$M_z_A=6(300)=1800$

I am just unsure where to go from here? Or is this all wrong altogether?

 

[Saladsamurai]

I have done this one over soooo many times. I am clearly missing a crucial conceptual point. ANY hints or criticism would help.

 

[Saladsamurai]

Well Good Morning!