The Zodiac Killer made a conscious decision to paste the wording "around in the snow" upside down, so one would like to think this has a purpose, in the form of a clue. Maybe if we had righted the postcard by inverting it through 180 degrees, the burial or deposition site of Donna would have become clearer. In other words, turn the postcard upside down to reveal where the killer placed the body. When we perform this task and place the pasted "Sierra Club" over the Clair Tappaan Lodge "Sierra Club" on a map, the punch-hole lands exactly over Camp Spaulding and Yuba Gap, where the skull and jawbone were found in 1985/1986.
The distance (by crow) from the Clair Tappaan Lodge "Sierra Club" to Yuba Gap is 14.32 miles, so if we divide 14.32 by 6.4 we get 2.24 inches in map distance from the Clair Tappaan Lodge "Sierra Club" to Yuba Gap. This still places Yuba Gap inside the punch-hole on the postcard (check below). There is reasonable leeway on the east-west axis either side of Camp Spaulding where her remains could be pinpointed more accurately in the future, and they would still fall inside the punch-hole on the Pines card. We also know, according to newspaper reports, that the remains were identified approximately one mile northeast of Interstate 80, alongside a mountainous road (likely Lake Spaulding Road) by Melvin Bennett on his way to Yuba Gap and Lake Valley Reservoir. This area falls comfortably inside the punch-hole. There is a 1.80 mile stretch of road that can fall inside the punch-hole (anywhere from 14,20 miles to 16.00 miles from Clair Tappaan Lodge). Whatever the case, the 2.39 inch measurement between the pasted "Sierra Club" (if Clair Tappaan Lodge) and the center of the punch-hole, can be shown to point towards the location of Camp Spaulding (irrespective of the exact location of her remains). This distance may not have any relevance if my interpretation of Zodiac's thought process and the design of the postcard is wrong.
FOLLOW UP ARTICLE: TWO POSTCARDS, TWO BURIAL SITES?