Need advice one audiopath...

If I wanted to use my mpc 2500 as my master for everything... what would be the best way to hook up my sp 404.. and another sampler such as the Octatrack ... so I can resample back into the mpc.. just trying to visualize the audio path.

Simplest way
Use a pair of the Mpc outputs other than the mains send that out to the other units and back into the Mpc. Once you find the sounds you want to effect just assign them to the output pair that is connected to the other samplers.

There literally endless possibilities of how you can have them set up. From those same outputs going into a mixing board and the mains of the mixing board going into the other samples and back into the Mpc. The octa track has two set of inputs which essentially could be a mixer in itself.

So are the outs just like the cue outs on the Octatrack?

they can be. I am only saying that because you may want to only sample and manipulate say the loop minus the drums. you can always run right out of the main outs but you have more flexability routing whatever you want sampled to specific outs.