Well, with a Maryland carry permit, things look really good, regarding handgun carry, along your stated route:
https://handgunlaw.us/states/maryland.pdf
Seriously, if practicable, get a Maryland resident carry license/permit, before the move. It appears that each state along your route recognizes an MD license/permit to carry. Another best move would be to get a non-resident permit for Texas, before the move, but realize that not all states recognize non-resident licenses/permits.
Without a MD carry permit, one can abide by the federal Firearms Owners Protection Act, or FOPA, for short. This means, in summary, carrying the firearms unloaded, in a vehicle trunk, or, if in a vehicle without a trunk, inside a locked container, separate from the ammo, as far from the vehicle occupants as possible.
Without an MD permit, one may well be able to carry loaded handguns INSIDE one’s vehicle, in some of the listed states. This does include Texas, as I type this. Check each state’s page, at the Handgunlaw dot US site.
Some of the states on your list appear to allow permit-less “open carry.” Again, the Handgunlaw dot US site is a valuable resource. Notably, Texas is NOT one of the states that allows permit-less open carry of handguns! Open carry of handguns, in Texas, with a few exceptions that are mostly related to hunting and the shooting sports, requires that one has a License To Carry A Handgun.
Texas is notably VERY long gun friendly, at the STATE LAW LEVEL. Loaded or unloaded makes no difference, in Texas, with long guns. Concealed, or unconcealed, makes no difference, in Texas, with long guns. Not all states are as long-gun-friendly as Texas.
Keep in mind, the federal “gun-free school zone” law. This a reason that I recommend getting and maintaining a carry permit/license from some state. Search for this, on line, and be informed.
Keep in mind that laws can change. The Texas legislature is in session, right now, and could make changes.
Do not trust ANY old copy of the Texas Penal Code, especially, because there was a FUNDAMENTAL SHIFT regarding firearms laws, a few years ago. Specifically, one change was that the “traveling defense” was DELETED, and with it, one of the few ways that one could open carry, inside one’s vehicle, without a License To Carry a Handgun. Now, one can carry a handgun, inside one’s vehicle, in Texas, but the handgun must be concealed, unless one has a Texas License To Carry A Handgun, or a carry license from a state that Texas recognizes.
Texas does not issue a “Concealed Carry” license. Texas issues a License To Carry A Handgun.
I am not a lawyer! Nothing I have typed is “legal advice.” I have done my best to be understandable.
I did enforce Texas criminal law, from 1984 to 2018.
Welcome to Texas!