One comment (which will no doubt go unnoticed) ; There is no "need" for a "guest worker" contiguous state law. Why? Because they are contiguous, that is why. Practical and enforceable measures for those living next door have to be a bit different from those for those who arrive from farther out.
What would work for us would be " Anybody from a state contiguous to the Continental United States and who has applied for routine non-quota permanent immigration, may, while waiting their turn, enter the USA and seek employment, provided they faithfully promise to return to their country of orgin once or twice a year for a period or periods or time of at least 60 days. AND post a performance bond to that effect.
Hey, It is only fair. If the Estados Unidos provides the yobs, the Estado Unidos gets to collect the mordida!
Will this proposal (If actually read) get some commenters frothing a the mouf'? Of course. But is it a decent proposal. I rather think so.