Welcome to the forums Lynda.
To answer a few of your questions:
1. Batteries. Typical batteries supplied with an RV are Group 24 or 27 12v "deep cycle" batteries. What is of concern to RVrs is the "Amphour" ratings on the coach batteries. A group 24 battery has about 75amp hours of storage. Two would therefore have 150 amphours. Your gas furnace will use 7 amphours of power while it is running. Therfore if in a 24 hour day it runs for 10 hours it will use 70 amp hours of power from your batteries (7 x 10). Add to that all the other 12 volt items like lights, water pump, etc and you can see that if it is cold outside you will have used over 50% of your battery bank capacity in only one day without hookups! That's not good.
On the other hand. 6 volt batteries are true deep cycle (12 volt batteries aren't really), have thicker internal plates and typically have around 230 amphours of storage. Therfore if you have two of them, you get 12 volts and 230 amphours of power, much better than the two 12 volt batteries at 150amp hours.
2. Solar: If you plan to dry camp a lot (no hookups) then you might need a way to recharge your batteries. A Honda portable generator is much cheaper but if you don't like to hear it running (they are very quiet anyway) solar is a good choice. We installed 2-130watt panels with tiltable racks and a 30amp 4-stage charge controller with digital readout and it cost around $1500US. Therefore if someone is telling you $1500 for one 130w panel they are ripping you off. Whether it is "better" than a generator depends on your power needs and only you can answer this. We tend to be power hungry and like to watch about 4 to 6 hours of TV a day if the weather is bad and we can't fish
If the temperatures are cold then we have to run the furnace and 2-130w panels have a hard time keeping up with this demand, we may have to add more. I for one don't like to run my generator if I don't have to, but sometimes it is just necessary.
I highly recommend you read The 12 Volt Side of Life
for a good explanation of everything power related including solar charging and inverters.