CGS 53a-109(a)(1) states: Such person enters or remains in premises which are posted in a manner prescribed by law or reasonably likely to come to the attention of intruders...

Q1: Does CT have a specific set of guidelines which detail how to post, that would fit the statement "are posted in a manner prescribed by law"?

Q2: Does the part after "or" "reasonably likely to come to the attention of intruders" mean anything not specific to Q1, but generally accepted and (obviously) conspicuously posted? Like how purple paint is a lawful "signage" in a lot of states?

There is a 2002 OLR doc on trespassers, invitees and licensees on private property:
https://www.cga.ct.gov/2002/rpt/2002-R-0365.htm

Sec. 53a-109 is "Criminal trespass in the third degree" statute. Note the following statute: Sec. 53a-110. Affirmative defenses to criminal trespass.

There is also a simple trespass statute: Sec. 53a-110a. Simple trespass: Infraction.

Don't see any specific language in a quick search that lays out what specific signage one is mandated to use to prevent/notify trespassers.

Also see the criminal jury instructions for 53a-109: https://www.jud.ct.gov/JI/criminal/Criminal.pdf#page=992

@sbhaven
Yeah, I read all those before posting (all but the criminal jury pdf)
I was really after this one

I'm guessing that, if you or anyone else isn't aware, we don't have specifics.

I'll proceed w/ what I find to be an average of other state laws (especially this area) so it would be "commonly accepted".

I'd assume so long as you put up copious Private Property / No Trespassing signs at the perimeter of the property and on the building (entrances) that should suffice for legal notice.

Example signage: https://www.homedepot.com/s/no%2520trespassing%2520sign?NCNI-5