The Newbie Gearhead Says "Hey"

Hi people, I am a total newbie to RVing. Been a hot rodder forever so with working on an older unit I made the jump. Got a super nice low mileage 1988 Honey Sportcruiser on a C30 Chev chassis. Heat, A/C, fridge, shower, toilet, most everything I wanted and most everything works! It has most of the original paperwork so I figured things out except these that I hope someone might be able to help me with. Also, what about this unit in general? Was it well made, or considered an also ran?

1)Dometic fridge works on electric and gas. When it runs on gas the light on the bottom panel that is part of the lighting secuence steadily blinks and every time it blinks I hear a small pop or spark. Normal?

2)The first time I tried to use the self ignighting water heater it blew the fuse. Where should I look first?

3)The LP bottle is old and rusted, I would believe the thing to do would be replace it. Where is the best place to find a new 65lb horizontal bottle ( yes I want one that big, that is what is there now ).

4)The ceiling lights directly behind each front seat have no power and I can't find where they are fed from. Does anyone know?

Thanx in advance for your help and advice because I only have one chance to make this work. If Mama ain't impressed the first time there is little chance of there being a second time.