Well, gun laws make otherwise law abiding citizens accidental felons. They also condition law abiding citizens ask for permission first.
Why would you need any paperwork for any firearms you are transporting? Does your state have any law that requires you to keep such paperwork and show it on demand to an officer? I understand that Maryland has a registration requirement for certain firearms, including handguns, but does that registration requirement include you keeping a record? Under normal circumstances this would be nonsensical, as the state's registration database is the legal source of information and not a piece of paper the owner has, like a transaction record. However, you live in one of those nonsensical states, so figure out what your state's laws are. Ask a 2A lawyer in your state!
If there is no documentation requirement in the law, then you don't need any documentation. You have no duty to proof that you lawfully possess something. In contrast, the state has to proof that you unlawfully possess something. At least, that's what the Constitution says. Your state may not care much about that, so if an officer seizes your firearm because you can't proof it's yours, you file the firearm theft paperwork with the ATF. If you are unlucky and run into civil asset forfeiture, then you can't do anything about that. This is legal theft by the state.
My advice, transport the firearms you have. Don't speed! Make sure that your car is street legal (e.g., all lights work)! Don't drive aggressively. If you get chased by a MD law enforcement officer, drive across the border and stop there. Preferably at a public place with lots of witnesses. If you are getting stopped, do not consent to any search or seizure. Know your rights.
Alternatively, hope that a professional sports player beats his girlfriend unconscious, the DA lets him enter a Pretrial Intervention Program, and you get the same DA. That worked for Shaneen Allen in New Jersey.