I'm not in the Baltimore area but I'll comment. I have never been a fan of any coops you purchase ready-built. They seem very expensive for what you get and they usually do not hold nearly as many chickens as they claim unless you have the perfect climate, lots of space for them to roam in all the time, and use more intense management practices than most of us want to practice. They do look nice and if you choose the right size for your number of chickens, they are certainly an option.
If chickens are confined in a run, they will eat and scratch away any and all green stuff in there fairly quickly. This is what 8 chickens did to a 64 square foot area in about 3 days.
It did rain so this may be a bit more severe than normal, but not much. Are you sure you want a mobile coop and run so they can move around your yard? Just a thought. If you do, then you should be looking at a chicken tractor. You do need to move those pretty often.
If you are comfortable building them yourself, you can look in the coop design section at the very top of this page for ideas. There are lots of great ideas.
Space is a big issue in keeping a small flock in the back yard. There are a whole lot of different things that go into how much space chickens need. The more usable space you can provide them, the happier they are and the easier they are to manage. We tend to use a rule of thumb of 4 square feet in the coop with 10 square feet in the run for each chicken. Those are not magic numbers that guarantee everything will be great and magnificent, but it is a good starting point.
In your situation, you can probably get 16 square feet to work, say a 4' x4'. Inside the coop you need a roost. You need a minimum of 8" roost room per chicken, with a little more room better. It's not that they take up that much room when they roost. They don't. But they need the extra room to spread their wings when they hop up there and maneuver for space.
You need room for a feeder and waterer positioned where they don't poop in them when they are roosting, if you feed and water inside. In a small coop like this, that gets difficult, but it can be done.
The only other thing you need is a nest box. For 3 or 4 hens, one should be enough. They will probably all use only one even if you provide two. I'd suggest two anyway. Some breeds and some hens within those breeds go broody more often than others. When they go broody, some hens keep other hens out of the nest box. Some don't mind other hens getting in with them and laying, but some do. If you only have one nest box and a hen goes broody, you could have a problem. That's why I suggest two, even if you hardly ever need the second one. If nest boxes are off the top of the litter enough that chickens can get under them, they do not take away from usable space in the coop. Chickens are basically ground dwelling birds so the only space that counts in keeping them happy is the space on the ground. Another complicating issue is that you want your roost to be noticeably higher than the nest box. Chickens will normally roost on the highest thing they can get to. If that is the nest box, they roost there and they poop a lot at night. You don't want them laying eggs in a poopy nest.
One of the issues for you will be poop management. As long as the coop and run does not get wet, it will probably not stink. If they get wet, they can small pretty bad, especially if the poop has built up. And if the poop builds up, it can get wet on its own, without any help from rain. So the main thing is to keep the coop and run dry and not let the poop build up. There are different strategies to achieve this. One that comes in helpful to a lot of people is a droppings board. They poop a lot at night, so if you have a board under the roost to catch those droppings, you reduce the poop load in your coop and you have great stuff to put in your compost pile. Not all of us have droppings boards, but many do, especially in the smaller coops. Some people scrape them clean every day, some use longer intervals. We all have different management techniques and practices, but I suggest you consider a droppings board in your coop.
Chickens need a well-ventilated coop. Part of that is to get rid of the heat in the summer so they don't cook. They wear down coats year round so heat is more of a danger than cold most of the time. But they also need good ventilation in the winter. The ammonia from their droppings can cause respiratory problems and the humidity that builds up from their droppings and their respiration can lead to frostbite. As long as you provide them a well-ventilated coop so the humidity and ammonia does not build up yet you keep them out of a direct breeze, most chickens can do quite well in temperatures you will likely see in Baltimore. I'll give you some links that talk about this in more detail from a lady that lives in Ontario. The way I achieve this ventilation is to have vents above the chickens heads while they are roosting. Hot air rises, so this way the ammonia and humidity can exit without blowing on the chickens.
I guess the other main consideration for your coop is that you need to be able to access all parts of it. Cleaning is part of it, but you will have other reasons to want to get to all parts. They may lay eggs anywhere or you may need to reach an injured or ill chicken. Ease in cleaning it is also important. I like walk-in coops but that may not be the type you want. It can be quite convenient to pull a wheel barrow up and rake the stuff directly into it from an elevated coop.
I'll quit for now. Hope you get something useful out of this. Here are those links. I think they should be required reading for anyone who is thinking about a coop and run. Good luck and welcome to the adventure. I think you will enjoy the journey.
Pats Big Ol' Ventilation Page
https://www.backyardchickens.com/web/viewblog.php?id=1642-VENTILATION
Pats Cold Coop (winter design) page:
https://www.backyardchickens.com/web/viewblog.php?id=1642-winter-coop-temperatures
Pats Big Ol' Mud Page (fixing muddy runs):
https://www.backyardchickens.com/web/viewblog.php?id=1642-fix-a-muddy-run