Motorhomes have LP tanks that have to be filled at a propane dealer. Some gas stations do this, just Google for your area. Yes you have to take the motor home to them or hire a service to come to you.
Leveling jacks- might want to check the fluid level as a start.
Water leaking heavily, may have a low point drain valve used to empty the water lines for winterizing, might be left open, or maybe a drain from the water heater, could have a valve that is left open. Otherwise just have to chase it.
Where are you plugged in? If you are plugged in using the big 30 amp cable to a 30A plug, you should have been able to run 2 heaters but not much else, unless the breaker you are referring to is the inside circuit breaker and you might have both heaters plugged into the same circuit. If you are just using an adapter to make the 30A cord fit house current then you won't be able to run two heaters on high.
Not sure about your specific motorhome for your more specific questions but I will tell you that if you post your questions separately you will get better response, especially from those who owned or own what you have now.
Congratulations, it looks great.
