There is no 90 day rule for AOS (I-485). That's a DOS rule...AOS is handled by USCIS.
Or you can marry and do do consular processing for an CR-1 visa if you want. But know that the ETA on that is ~12-16 months, so a June/July date would be very unlikely to be able to have the visa.
A K-1 (fiance) visa is taking ~8-12 months right now + you would then still need to file for AOS + an EAD. The EAD is taking ~4-6 months now, so the June/July date is highly unlikely as well.
It doesn't matter where you marry. That said, the first option (AOS) is only valid while you are already in the US and did not intend to stay. You can't go to Canada to marry (or take care of any loose ends) then return to the US with intent to file for AOS.
