Another Battery Question

[RMcNeal]

I've been doing some pricing/research on batteries for the rig and would like some advice from those more knowledgeable before I pull the trigger. Let me start by saying we are not full time, but long time, like 60-80% of the time in rig and we NEVER boon dock. I have the residential refrigerator, so keeping it running during travel days and power failure is my primary concern. Our typical travel days do not exceed 4 hours. On some rare occasions we may go as much as 6 hours if absolutely necessary.
I currently have one 12v Road Hawk Predator RV DC27 AGM battery installed by CW when we purchased the unit new last October.
This battery is not keeping up with the refrigerator during very hot travel days even though fully charged. Truck charging circuit is good, I checked. Refrigerator is the new Samsung which lists 3 amps max draw (really? that seems low). The original battery box that came with the unit appears to be just large enough to hold 2 group 27 batteries with no room to spare.
I have narrowed down the battery search to 2 options:
1. 2 12v Group 27 batteries at 90 AH each for about $90 each
2. 2 6v GC2 Golf Cart batteries at 230 AH each for about $130 each
Option 2 will mean replacing the battery box at about another $80-$100.00.
Option 1 means I will have about 90 AH usable at about $1.22 per AH.
Option 2 means I will have about 115 AH usable at about $1.13 per AH.
Both are flooded cell batteries. My converter will not do lithium and the cost is extremely prohibitive anyway, so they were not even considered. AGM batteries appear to be around twice the price, not a deal breaker, but I don't mind the minimal maintenance of the wet cells. I'm pre-wired for solar and generator but have not added either one. I doubt I ever will add solar since we don't boon dock.
Does the 90 or 115 AH seem like enough? Is the extra expense, $140 - $160, really worth around 25 AH of usable battery? Any advice appreciated.