Hi, I also stay with my GF in her home and go through this drill every year. She needs to do the TM30 within 24 hrs of your arrival - easiest way is online (use link posted above). I actually do this for her, it's simple. Then print a screen grab of the TM30 and take this with you to immigration when you are applying for the extension (I presume that's your objective). She does NOT have to accompany you. My GF has never done so.
Similar situation, I stay 5 months, 1 SE tourist visa + extension, border bounce (though usually do 4-5 day trip), visa exemption + ext. If I wanted to stay 6 months I'd a get a tourist visa from the neighbouring bounce country. Don't see any point in retirement visa for just 5-6 months.
Free travel insurance is usually a gimmick. With my card, the first 5 days are free if you are under 60. If over 60 it's 2 days free. Then of course to get the free days you need to take out a policy for the duration of your trip.
the OP applied for single entry visa, not multi. But in any case, it's not true that the visa will be denied if he says he will enter visa exempt. I was in the exact same situation last year and they actually encouraged me to enter visa exempt. They also agreed to delay processing of my visa so I could use it for my next planned trip. Also the OP cannot "try the Vancouver consulate", you are required to direct your application based on your residence location.