Is that a group 24? Think 2 group 29, GC2, SCS225, J185H etc (large batteries)
Do you keep it plugged in at home or let it run down between trips?
Did it actually get below freezing? That will be a lot of furnace time as you get below 35F and really drain the battery. You also risk general fresh water system freeze and damage if you are not running the furnace.
Minimum 2 batteries if you will be running the furnace off grid.
For the price of a generator you can have a nice solar charging system to maintain the battery when camping or in storage. Otherwise a Honda/Yamaha 2000 will work fine.
If you do get a generator you also need to review the converter is adequate for charging in reasonable time.
The 12 Volt Side of Life