Renumbered as part of the modern 28 around 1937 (definitely by 1938). 
 

284 ran as far north as Waynesville by 1924, and was extended into Tennessee by the middle of 1930. Most of the road itself is much older that that -- as just one example, 284 was partly signed over the Pisgah Motor Road, which dates from the 19th century. 

U.S. 276 replaced 284 as 276 was extended north over the years. The stretch from Brevard south to S.C. was gone by 1932. In 1939 or early '40, 276 was extended all the way north to Waynesville. (A short stub of the old 284 that 276 did not replace -- SR 1512 in Transylvania County -- may have been part of N.C. 280 for a few years.) A short stertch of road from the center of Waynesville north to U.S. 19 was renumbered between 1959 and 1960. Finally, when I-40 opened in 1967, 276 was extended north over 284 for the last time to meet the Interstate. 

With the opening of 40, all of 284 was killed, including the Cove Creek Road portion northwest of exit 20 that 276 didn't replace. 

Most of Cove Creek Road today lies with GSMNP, and is thus under National Park Service control. Save for a short stretch near I-40, it remains unpaved and unimproved. If you want to know what most mountain roads were like 80 years ago, this is the one to drive. 

Cove Creek Road crosses into Tennessee at Davenport Gap (elevation 1975 feet). The Appalachian Trail leaves the national park and crosses the road here. A stone bearing the inscription "NC 1821", as well as a remarkably unpretentious "NC STATE LINE" road sign (Image #2), marks the state line. 

Upon entering Tennessee, old 284 becomes paved state highway 32. For 12 miles west to U.S. 321, Tennessee 32 is extremely twisty, rivaled only U.S. 129 on the other side of the Smokies. In fact 32 is probably twistier, but it's not as well known as 129 is. 
 

In 1927, 285 was extended south into Georgia over what had been N.C. 286. See Image #3. 

285 was killed in 1933 at the beginning of the great renumbering. 
 

In 1927, 285 replaced 286 south of Franklin. See Image #3 above. 

In 1937, what remained of 286 was renumbered as part of N.C. 28. 
 

Much of old 287 probably lies under Chatuge Lake today. I can't confirm this yet, but maps very strongly suggest it. Pre-1940s maps (such as Image #4) always show old 287 heading southeast away from Hayesville, whereas post-WWII maps (Image #5) show modern N.C. 69 running due south. The alignment of U.S. 64 changes during the mid-1940s, as does the mileage on U.S. 76 in Georgia between the town of Hiawassee and 76's junction with highway 69. From Hayesville, 287 most likely ran over modern Sanderson Street (SR 1140) before reaching the lake. 

By 1946, the Hiwassee River was dammed and two-state 69 was relocated away from the lake. Georgia has renumbered its 69, so that today, N.C. 69 continues as Georgia 17. 
 

The road shows up on a 1901 topographic map. It was first signed as N.C. 289 between 1928 and mid-1930, and demoted to SR status around 1939 ('39 official map shows it, '40 doesn't). Its easternmost 3/4 mile, now SR 1334, may have been renumbered to N.C. 292 in the early 1930s. 

289's southwestern terminus was at the old N.C. 284, so the original numbering system was obeyed. 

If you're familiar with N.C. 209 -- if you've read this far, you must be -- heading north on 209 there's a place where the road makes a sharp turn to the right, and to the left is a "To I-40" sign. That road to the left is the old 289. It hits 40 at exit 15. 
 

A primitive road from Fines Creek ran north to the Haywood/Madison line by 1901, and completely to Max Patch by the mid-1920s. Max Patch was used as an airplane landing site back then, so presumably a road was needed. It first shows up as 292 on 1932 maps. It along with nearby 289 was demoted to secondary status around 1939. Today, the road continues across the state line as paved Tennessee 107. 

292 violated the state's numbering rules, in that it did not spur from N.C. 29 or a 29x route. In fact the original 29 had no 29x routes, and was renumbered before 292 was first signed. The state had used up all the 28x (and 20x) highways by the time 292 was formed, justifying the use of a "nonconforming" number. But why didn't the state use 290 or 291? 
 

This road was commissioned as N.C. 293 in 1932 or early 1933. The road itself shows up on 1920s maps. In fact, a 1922 map shows a primitive road continuing west of Soco Gap to the community of Cherokee, similar to U.S. 19 today. 
In late 1941, 293 was extended east to Cherokee over a newly-paved road.