I just bought the antenna David had bought shown here Reach M2 w/ Mini-Survey Antenna Static/Rapid Static Testing Results
I’m satisfied with the supplied M2 antenna that Emlid sells with the M2 but it’s not in NGS’s list of calibrated antennas. Swift’s antenna is reasonably priced at $225 and comes with a 4 meter cable. You can use the M2 cable and connect to it without any adapter. It also picks up Galileo sats; it’s not mentioned on their website.
As far as surveying in the woods with the M2 or any other receiver, I would be extremely cautious with any "fixed’ solution. To verify, I would either PP with a closed loop or re-observe the point. Javad receivers, which we have, are the only receivers that can penetrate high multi path areas and guarantee a fixed solution. I’ve used most of the popular receivers and Javad’s are the best