Mine (not all CCC type projects):
1) Expand GSMNP into surrounding National Forests. This would require resurfacing US 129, as an ancillary benefit.
2) Build new trails in Bankhead & Talladega NF, including trails that actually go to the places I like to go.

3) Repave Foothills Parkway, and repair that darned landslide area. If we really want to waste money, build a massive tunnel to connect the unfinished ends.
4) Repave Blue Ridge Parkway, and remove the white boundary lines from Skyline Drive.
5) Totally revamp Amtrak. This would include new rails for passenger-only traffic, and a passenger rail link through Canada to Alaska. Allow dogs.