Shakedown weekend questions

Newbie here.  I've learned a lot reading through this site. We went on our shakedown trip this weekend in some cold, nasty weather.  Here are my issues I am still somewhat muddy on.

1-  is the water pump only needed when using Fw tank? Doesn't need turned on when Hooked up to city water connection?

2- I have 2 6v 230ah golf cart batteries in series.  I put a shut off switch on them.  When I am towing, will they charge regardless of the shut off switch being on/off?  Will they recharge on shore power regardless of being switched on/off?

3-  I just bought a volt meter to keep connected to the batteries for a better sense of how charged they are.  What is too low.  What is fully charged?  At what reading do I need to worry about recharging?

4-if my batteries are seeming low, can I just hook up my connection to my truck and let it run for awhile to recharge, or does it need to be in gear?

5- when boon docking, is it more efficient to run the fridge on battery or propane?

6- we are debating between adding a 2nd 20lb propane tank (new mounting frame &a cover) or trying to fit a 30lb tall tank with the factory set up.  Has anyone fit a 30lb tank without modifying?

7- I have a 2016 Ford F-150 with the deluxe tow package.  It doesn't seem like my batteries are recharging when I tow. If I'm running the fridge, will it not be noticeable? How long does it take to see a significant increase? Will they still charge if they are shut off? I'm thinking an hour and 

A half tow wasn't long enough to notice an increase.

Thank you for answering in advance! I'm sure I'll have some more questions before long.

Laureen