Here's a Link to a notice which appears to be very well made:

http://landrights.com/NoTrespassing.htm

I have not as yet fully examined the site it is in, but it looks good/useful as well:
http://landrights.com

My question about this notice is as follows:
Would it also be useful to post this upon a window of our personal conveyances ?

I have downloaded it for my own usage and found it is very easy to rotate a bit for ease of reading on the PC's screen.
Was tempted to post that copy of it here, but didn't know if it would be OK...?