Need advice: have been stucked in TN for past 3 years...

I see your point but my point is that you do not need to seek US PR but valuable US work experience. So no need to worry about the easiest path to PR or the system etc. as you have to look at it as experience. Don't link the two is what I say.

Look at a work permit for what it is.opportunity to work for a while in a country. Be it US or any other country. Do not link that with permanent residence as each country has its own requirements and issues surrounding that.

So there is no catch really if you go forward and approach it as a temporary stay.

To join the debate. Well for those of us with college-going TD dependants it is a big economic disincentive to be on TN as our dependants are charged out of state tuition. However, H-1 dependants are allowed in-state tuition. So this is also one reason to seek H-1 or permanent residency status but I think there are some states that allow in-state fee to TD folks.

Make more sense to do F-1 than TD for college students, they can work on F-1 but not TD. Doesn't solve the tuition problem though. Presumably they would have to go to F-1 when they reach 21 anyway.

However, H-1 dependants are allowed in-state tuition. So this is also one reason to seek H-1 or permanent residency status but I think there are some states that allow in-state fee to TD folks.

I looked into this, the answer is "no" for TD and usually "no" for H-4. A few States (the big ones) do allow it for H-4 based on a court case in California but the vast majority do not, although I suppose you have caselaw there you could use to challenge it.