I've just installed it to P3Dv2
and FSX with no issues at all. I'll tell you how - you can tell it where the target sim directory is, but it actually installs the files you activate into wherever your photo scenery folders are. Mine are on a disc with only about 1.5GB left and it completely ate that up, so I had to uninstall some stuff to fit it all in (nice of them to warn us beforehand...).
Unfortunately, I don't have time to test it this evening, in-sim, but I will try tomorrow and definitely over the weekend, in both sims. I am planning to do a short (5mins approx) video to upload to YouTube - so you will be able to see for yourself, though my video quality is low due to my very slow upload speed requiring as small a file as I can manage.
The guy on JF's forum said what he'd seen of it so far looked good.
There is some talk about treescapes on the Overclockers UK forum - apparently it is possible to do some file fiddling, but no info on exactly how - so if you ask the guy who posted it (you'll have to do what I did and Google it, I'm afraid) he might tell you how he does it.
Thing is, from what they are saying, I understand that any scenery you have above the Rev.X entry in your library will show up as normal - so if treescapes is entered into the scenery config, it shouldn't be a problem.
You can also install just a part of the RevX stuff - i.e. only a single volume of your photo scenery or any number of volumes as you require.
I'm going to go and take some screens of the GUI - back soon
Here we are:
Oh, and btw guys (and especially you, Dave, as you are concerned) you can use your own textures over the top. So if you use, for example GEX, like I do, you can add them in after you have installed Rev.X and it will use them instead - it says that in the instructions on the GUI. So if you have some decent (i.e. UK-style) building textures to replace the default autogen ones with, it will let you do that, and use those as the 'pop-up' buildings instead. Sounds good - hope it is that easy!