I liked the episode... It worked ok for me.
Re: the weapons stuff, I think it's as likely this is private stash crap as it is military hardware... But regarding accuracy in general, I'd take it all back to the two tanks in the show and say not to think about it too hard.

But yeah, I mean Abraham hasn't had a military issue M-16 in eons I'd wager. And who knows where that soldier got the RPG's... It's the south.

Norman Reedus has leaked it that the voice on the walkie talkie isn't Glenn. At least that's what he's saying anyway, rather emphatically.
Re: the forest fire, also keep in mind there appeared to be something of a major drought going on not TOO long ago... It's possible the fire was just ripe for a fire. I live in an area where burning garbage is still legal, and trust me it doesn't take long for fire to spread. You don't need gas if things are even relatively dry, actually.
I think the fate of the two that yoinked Darryl's bike and bow are either A) they wind up running into the mega herd and we see remnants of this, or B) they wind up at Alexandria somehow and Darryl gets to see them there. Either way he's getting the bow back. I can't see that not happening.
Oh, and I'm with Bill... I'd want both.
Oh oh, and I'll add that I too didn't catch a lot of the subtle stuff this ep, like Patti and all that. I got the two glass zombies thing but other stuff was hard to catch. Hell, even the thing on the walkie talkie at the end was something I didn't hear at first.
This felt like a lot of Darryl fluff, but supposedly this all somehow plays into the future in some way... Or so sayeth Norman Reedus. I'm not sure who the well armed group was, but it's not unheard of for any old random group to turn up too. The Philly Crew after all.