Now that TS10 has the ability to copy and paste that works with splines as well, yes you can, but its long winded and laborious.
To help, I've made an object that's basically a 720x720m square with a cross in the middle.
Place a grid of these objects over your existing route, coinciding with the individual baseboards.
Add extra baseboards to your route, in the same pattern, but obviously rotated through 180 degrees.
Place a grid of the objects over the new boards.
Copy a board at a time from the original part over to the new part, with all the options (absolute height, textures, objects and track) enabled, and the direction set to south.
The cross in the middle of the new object gives a reference point to paste onto, if it appears to jump, then you've pasted into slightly the wrong position.
Delete all your original boards, and these new objects.
Join up all the splines that were split across baseboard boundaries.
There you have it.
Long-winded and laborious, but it works.
If you're interested in this object, PM me with your email, and I'll send a cdp as its not on the DLS. Yet.