Battery life off-grid

First question is what type/quantity batteries do have? You mention batteries plural so I assume you have two. The best solution is two 6 volt galf cart batteries in series. That will give you about 220+ Amp hours storage. If the dealer gave you the standard Gp 24 12 volt battery(ies?) you should replace them with the two golfers. Trojan T105s are the gold standard, but Interstate makes a heavy duty GC2 almost as good. Recharging cell phones and tablets are very low power; no problem recharging but the chargers should be unplugged when not in use. The biggest power user will be the furnace fan and that's a function of outside and inside temps.

Will you have the tow vehicle nearby? The easiest recharge in the field is a good heavy set of jumper cables from your TV battery. Don't skimp on these. All copper, no aluminum, and #2 or #4. I would think one charge of 2 hours midway in your trip should be adequate. If the TV is not available and you switch to the golf cart batteries you should still be OK, but just a bit closer.

I can't speak for R-pod battery life, per se, since we haven't dry camped in ours for more than one night so far.  But we dry camped exclusively for about 20 years with our former popups.  One group 27 battery usually was good for at least 3 or 4 nights of occasional furnace use and minimal lights (non-LEDs).  The R-pod has a few more "parasites" to draw on the battery than our popups did, but if you have two batteries, even if they are group 24s, I would expect they would be adequate for the four nights you describe, provided you are very frugal on running the furnace and making sure you don't accidentally have the fridge set for DC, etc.

Our Pod came with a group 24, to my dismay, but I'm planning to add a second group 24, and assume we'll be good for a night or two more dry camping than we were with the single group 27 on our previous popup.

My TV is a tacoma and it has an electrical outlet in the bed that offers "400 W while idling".  Can I hook an extension cord to my truck's electrical outlet and connect that to the pod's outlet, as I would at home when charging the batteries?

I also have a couple questions on battery charging, since I will be dry camping in Yosemite this spring.  I have a Honda 1000 watt generator I plan on taking with me since it is allowed to operate one a few hours each day.  How much time does it take to recharge a depleted battery with the power cord plugged into the generator?

Wait... maybe I'm making this way too hard.  I can just hook up the 7 pin connection between the truck and trailer and let it idle while I cook dinner and putz around, yes?