Autodesk Inventor

[#1]

How may I best reuse a legacy assemlby and it's drawing to create/update to an vairant assembly?

[#2]

Not quite sure I get what you are trying to do, might be that I haven't had my coffee yet this morning.

But have you attempted to do a "save as" to the new folder location?

Are you wanting changes in the assembly to be reflected in other associated assemblies?

Are you using Vault?

[#3]

Not using the Vault.  I have an "top-level" assemlby that has three "sub-asseblies" that are nothing more than a variant of one another.  In other words, same parts in differnt locations and rather than building it three times and detailing the its drawing, I'd like to reuse the 1st build sub-assemlby and save it that has both shared parts and ones that only change in their length.  Under the File Save As there's a "Pack and Go" but I can't get it to go. :/

[#4]

I might just do a Save-Copy As and then just edit each assembly. Possible a screen capture to understand what you are trying to accomplish might help.

I can make a number of completely different assemblies using the same part arranged different ways in each assembly using 4 simple domino tiles all the same tile

1.) long row, end to end 

2.) short row, side to side

3.) flat surface, 2 up and 2 across

4.) hollow box

5.) stacked pile

I would want a new drawing for each one