Assuming I do want to take pictures of things like people, buildings and things further away, but not too far away. Does it sound reasonable to buy a 50-200 mm lens, when just considering the distance and not other photographic parameters that defines quality?
Usually a 50mm lens is where portrait lenses start. You will have limited composition abilities to make pictures of buildings, and that sort of things.
There is a reason why kit objectives are set as 18-55, or 18-105. The small focal length provides good field of view to create photos about large objects.
I suggest trying this simulator to experiment with different focal lengths.
You also have to note that bodies having different types of sensors (full frame vs crop) have different types of lenses, and an FX lens will have different effective focal length than a DX lens on an FX body.
And just to address that particular 50-200 mm - if I am right with the part, you should check the image quality first before buying that lens.
Most people would say no but a lens is truly about your vision. You can do architecture photography with that focal-range but not expect any of your images to show the entire building unless you are far away and there is nothing obstructing your view! You can however takes a large number of shots and stitch them together though.
That range is certainly usable for people and detail shots of things. Keep in mind though that, most such lenses, contrarily to a 70-200mm one, have a limited maximum aperture which is a key part of its specifications, you will get less light in and less background isolation as is usually seen in most portraits. The light issue is critical as it will also force you to use higher-ISO in order to keep people sharp because of motion blur.
The second part of your question is completely unrelated. Lots of things define the quality of a lens (sharpness, distortion, contrast, chromatic aberrations, vignetting, etc) but the general parameters like focal-length and maximum aperture do not. Price is actually a more steady indication of quality, although there are exceptions too.
Assuming you are using an APS-C or Full Frame digital camera or a film camera that uses 35mm film the 50-200mm focal length range allow fields of view appropriate for "...things like people, buildings and things further away, but not too far away." In the end what focal length is appropriate depends on what you want the shot to look like as well as the size/distance of the subject matter.