Need advice getting TN to save relationship

Hi Everybody,

I'm new here, and creating an account in hopes to put my mind at ease by getting some sense of direction.

I've been involved in a committed long-distance relationship for 5 years now and recently starting looking into my options on how to make a living in the United States. I understand that if we marry , she could sponsor me for a green card, but we'd like to see what first living together is like first before we jump into ring territory. The two options that seem the most popular is H-1B and the TN Visa. Being Canadian, I discovered my chances are better with getting a TN than the former.
I also have read and found that to apply for a TN Visa you must not show immigration intent when you apply at the Port of Entry; however, I have also heard that if you do later choose to immigrate, you can return to your home country and re-apply at the U.S port of entry to avoid any 'intent' assumptions and being barred. Is this true?

My educational background currently is: HS Diploma, Post-secondary IT certificate, IT vendor certifications, over 5 years exp in networking/IT, and pursuing a B.A in Information Systems. Once I have that degree, I'd like to start applying for jobs in the east coast of the U.S and start that life together that we so longed for.

So, based on my career focus and educational goals, would I qualify for a TN after I finish my bachelors? I've heard some people on this site have gotten approved for computer networking type of positions under the Engineer NAFTA profession, but they had degrees in engineering.

I truly hope I can find some legal means of getting work in the U.S so we can have a trial of living together before going to the altar. Any and all advice is welcome.

however, I have also heard that if you do later choose to immigrate, you can return to your home country and re-apply at the U.S port of entry to avoid any 'intent' assumptions and being barred. Is this true?

No, if you are on TN, and you amrry you MUST stay put in US until your GC application is submitted, and you get another working document, all while staying in US.
leaving US any time after you marry is a recipe for being locked out for at leadt six months while you apply for visa from outside the US.

From what I have read, that would be considered fraud because the TN Visa is a non-immigrant Visa. Wouldn't staying in the U.S as a non-immigrant with the implied intent to go back home while simultaneously applying for a GC be immigration fraud?

Your TN is legitimate, until you marry, at which point you simply adjust while in US.
If you marry and then leave US, you are inasdmissable until you get a CR-1 visa, by which time you lode your job.