I mostly disagree with your example (the use of RV's is nice, although I think it changes the equations too much) but I can grant you (and Malcolm Ocean) the point:
>Yes, this is the standard Georgist position, and it's the reason why land owners mainly capture (positive and negative) externalities from land use _around_ them, not in their own land.
Might we agree that positive externalities outweigh negative ones as evidenced by high land prices? If we take this position at it's best, at the end of the day, how is taxing the capture of a positive externality (LVT) any better than the taxing the creation of value (SQ)? (Given that the positive externality already exists and would be captured for free under the SQ.)
>The question is, which of these effects is bigger? I would say that landowners have more influence over their own land than over surrounding land, so a priori I would expect more density to result from an LVT
The effects you've identified I think are fairly comprehensive. However I think that "Moving to a less dense place" is actually a method to reduce density in the surrounding land i.e. picking up all the skyscrapers and spreading them apart (the regularisation effect over density) and is a decision which landowners frequently make.
This is a really interesting thought (which I will be using in future) but I think it arises from the fact that the tax incidence has to terminate on someone at the very end. Like say income tax (and a wealth tax), depending on how you cut the pie, there are multiple different options for the set of cash flows and corresponding total tax amounts. Moving the assets / cash flows to a business / trust / a separate business / an offshore business / another person all throw a wrench into the works. When we try reconcile infinitely complex real world processes onto paper, there will be problems.