You could try the Burnsville Metric or Fabulous Fourth Metric. The Fletcher Flyer is actually pretty flat by mountain standards and offers rides of different lengths. The Assault on Marion is run along with the Mitchell ride is also an option. The Assault on the Carolinas metric is coming up on March 29th.

There are also rides in the Hickory area at various times such as the Murray's Mill Metric.

SEBF has a group ride in May on the Blue Ridge Parkway. Details are here if you feel up to it.