In addition to numerous non-ACA routes, I have done the TransAm, Pacific Northern Tier, Atlantic Coast, Florida Connector, and Lake Erie routes. I have done parts of: Lewis & Clark, Great Rivers, North Lakes, Tidewater Potomac, & Washington Parks. Big "trails" include Katy and C&O.
Out of all these, the TransAm was my favorite but far. Scenery changes every few weeks, varied geography & people, lots of fly-over country hospitality, less traffic, etc. Overall, just a really great route.
On the "North America Bucket List": Great Divide; ride to Prudhoe Bay, AK or Dempster Highway in Canada; the new Sierra Cascades route, southern Tier. Of course, lots of non-ACA routes thrown in for good measure.
It's winter so keep dreaming but come spring start touring!