also can I use a bug bomb inside to kill whatever
I would NOT put a bug bomb in your RV. The square footage is too small for what one can is rated for safe use. And propane in too close proximity to use per their own warnings.
That and the chemicals can be deadly for your pets and you. NO matter what the can says about safe around pets after dry. The concentration in an RV negates any and all of the safe warnings. Even the brands that claim to be 'dry' spray will leave residue all over your coach.
Nope, I would not ever use a bug bomb in an RV. Just saying.
purchased 5th wheel, had not been out for about 1 1/2 yrs. turned on heater to check it out, had a different smell.
Read my posts about that. I found out that the 'smell' they add is not regulated by the gov. It can differ from propane company to propane company. So the smell you are accustomed to may not be the same smell that was added to the propane that is already in your tank when or where the previous owner filled it.
Did you purchase your RV from a different state than you live in?