Step 1. Review idea with wife & get green light

All and all not that hard actually.  My wife is not all that interested in my astronomy hobby, but she is very understanding of how much I enjoy it.  In the end the foot print will be smaller (versus the tripod I use now) plus all the cables will be buried, so the pier should in theory tidy things up quite a bit.

A sketch of my basic idea is to the left.  I will start with some gravel in the hole to provide better drainage and thus hopefully resist heaving.  I will then start the concrete with a pour that takes up pretty much the whole width of the hole.  Inserted in the concrete will be some galvanized steel fencing for reinforcement.  A 10" sonotube will then be lowered into place and braced, with fencing on the interior.  The sonotube will be anchored somewhat by some more gravel.  After all the concrete is poured I'll fill in the rest of the hole with the dirt I took out of the hole.  3/4" threaded rod will be inserted in the top of the pier during the pour, for use in holding the mount.  There will also be 4 x 1/2" threaded rods passing through the pier at 90deg.  These will support a wooden platform which initially will be just a work table to set my laptop on, but will eventually support the clamshell enclosure that I hope to eventually build.  The pier will be in the ground roughly 3' and protrude about 5', placing the mount itself fairly high off the ground (by design).