I speak from a somewhat different perspective... I am a 13 year veteran police officer. I work in a jurisdiction just outside of Washington DC that adjoins NE and NW Washington DC. I would routinely respond to calls involving gun violence... victims being robbed at gun point, having guns pointed at them after a traffic encounter, shootings, carjackings, etc. It happens WAY more often than most people think. Oh, by the way... In Washington DC it was ILLEGAL to possess a handgun, yet a lot of criminals had them. Maryland has some of the most restrictive gun laws in the country, yet a lot of criminals had them. Strangely enough, gun laws don't keep criminals in check. I can't figure out why a CRIMINAL who would commit a VIOLENT FELONY wouldn't cooperate with a misdemeanor gun law.
I support the 2nd amendment but I caution people about exercising that right. To be proficient you need to practice. The average lay person that bought a gun 10 years ago and takes it out once a year to shoot 50 rounds at a piece of paper in ideal lighting and with no stress factors isn't in the best position to use that gun on a moving threat in the dark who may or may not be returning fire. I am rather right-wing in my ideologies, but I feel that the 2nd amendment needs to be exercised by competent gun owners. I feel that if you want to CARRY a firearm outside of the house you should meet minimum criteria and submit to yearly minimum training (to include shoot/don't shoot scenarios, legal refreshers every year and ability to hit a target).
OP, to answer your question... its a question that hasn't definitively been answered around the country. I speak from experience in Maryland. You have the right to have a firearm in your residence, but it must be registered it if is a regulated firearm such as a handgun. To wear, carry or transport a firearm in public or places where the public is legally allowed (like a store) you need a concealed carry permit issued by the state of Maryland. They are VERY difficult to get. There are stringent policies and procedures in place to get one. In 13 years on the job, I have seen 3 concealed carry permits... and two of those guys were licensed armed security guards. Maryland does NOT recognize any other state's concealed carry permit.
In regards to your RV... it depends on whether or not the court rules that the RV was a HOUSE or a VEHICLE. A motorhome could be considered either a house or a vehicle, and I have read case law on both sides of the argument. It is a house because you use it as a residence... gun was legally in the house. It is a vehicle because it can de driven ... gun was illegally worn, carried or transported. A travel trailer makes it more likely to be a house, because it isn't a self propelled vehicle... but it is still a "vehicle".
Good luck and good argument. I have the legal authority to carry a firearm (almost) anywhere in the US as a law enforcement officer. I carry more often than not. I promised my wife that I would try my best to carry when I am out with the family. With our proximity to the nation's capital we have a lot of "high value" targets. The Navy Yard shootings from a couple of years ago... we had a triple fatal mall shooting at our local shopping mall a couple years ago. The world has changed...