Is there an easy way to move a plan's origin point?

[clbpdx]

Before importing from a surveyor .GPX file, I'd like to move my existing plan's Origin to be at a physically accessible and useful landmark such as a property corner pin.

Ideally there would be a way to enter a new Origin (similar to Transport /Replicate Object "Move" function), and everything else relative to it would update accordingly.  I wasn't able to find such a thing.

I instead tried to "move the mountain" by:

1. Assuring automatic rebuild was turned off for everything (framing / attic walls / roof / foundation)
2. Unlocking and displaying all layers
3. Selecting and moving everything on each floor using Transport / Replace Object by a calculated X,Y Delta.

This mostly worked, but there are lots of things that go wonky during the move such as beams and custom backspashes moving around, doorway that no longer goes to floor, bay window and its trim have shifted and has siding instead of glass and trim location moved, little pieces of wall and soffits moving around, etc.  I'd rather not spend time finding and fixing all these side-effects.

What am I missing?  Is there an easier/better way to get this done?  Should I give it up, do some math and just have the .GPX file reference my existing poorly placed Origin?

Thanks!