@Anonymous,
The approach will most likely depend on the end use of your character (i.e., still image, game asset, vfx asset, etc.). Many tutorials online will take you through the following general game asset process (limiting the pipeline to the software you suggested):
1. Create a base mesh in 3ds Max (this will serve no purpose beyond the starting point of your sculpt).
2. Sculpt your character in Mudbox starting with the base mesh. If the topology becomes unwieldy (e.g., too stretched, etc.), and further subdividing won't help, then retopologize in Mubox to get more uniform topology and continue sculpting. Use Mudbox's automated retopology tools for this.
3. When finished sculpting, you can choose to paint your sculpted character in Mudbox.
4. When sculpting/painting is complete, reduce the mesh in Mudbox (using the Reduce Mesh tool) and export/send the reduced mesh to 3ds Max for final retopology. The final retopology should be suited for your purpose (e.g., considering animation edge flow, etc.). The reduced mesh is only used as your retoplogy reference in 3ds Max. Your original high poly sculpted/painted mesh will be used later for baking maps in Mudbox (as described below).
5. UVW Unwrap your retopologized mesh in 3ds Max.
6. Bring your final retopologized and UV'd mesh into Mudbox and bake normal/displacement/diffuse/etc. maps from your high poly finished sculpt to the new lower poly retopologized mesh.
7. In 3ds Max you can then apply the baked maps to your final retopologized mesh. The result will look like the finished sculpt in Mudbox.
Voila!
