Castle Doctrine. If you don't have a CCW permit research your state's castle doctrine. For instance, you should be able to have a weapon in your vehicle, but without a CCW you cannot carry it into a gas station for instance. The same would apply to a hotel room. You can transport it from your car to the room, but don't go walking around the lobby with it...it needs to stay in the room. Not having a CCW doesn't mean you are defenseless.
I happen to know this was totally a grassroots event, it was not organized or supported in any way by the party or campaign, it was just a Trump fan with Facebook who wanted to support our President! And the cars did complete the entire bypass loop around Cincinnati. Many of the cars were full of very conservative religious people who were on the fence in 2016, but now would crawl across a mile of broken glass to vote for Trump!
I'm sorry for your loss. My last loving grandparent passed in September and it hit pretty hard.