Nice to talk with you Hal. Below are a couple of citations which explain why a Memorial or Plaque would be inappropriate.
In wilderness, facilities, installations and structures are prohibited. For the rest of the National Forest single focus use is generally discouraged and some types are prohibited, such as for monuments and memorials. There is the possibility of a small label of dedication installed on an existing feature outside of wilderness like a trailhead kiosk or a picnic table. You should talk with the local District Ranger about those possibilities.
From our Special Uses Manual – Uses which should be denied.
FSH 2709.11, section 12.21, paragraph 4
4. Will not create an exclusive or perpetual right of use or occupancy; that is, the proposed use would not in effect grant title to Federal land to an authorization holder or would not create the appearance of granting such a right. Examples of such uses that could in effect grant title, or give the appearance of granting such a right include:
a. Cemeteries, monuments, or other memorials; and
From 2320 Wilderness Management
2323.13 - Improvements and Nonconforming Facilities and Activities
Provide facilities and improvements only for protection of the wilderness resource. Document and justify conditions for providing facilities and improvements in the forest plan. Install facilities as a last resort only after trying education, other indirect management techniques, or reasonable limitations on use.
