How were steamboats of the 1800s landed?  Were docks required, or
could the boat just run up on shore?  How did they stop; did one just
stop feeding coal into the steam engine and coast to shore?  What if a
steamboat needed to stop or land somewhere which hadn't been settled,
where there weren't docks of any sort?

Any information will be appreciated.

Dear syrith,

I assume that your question refers to the steamboats sailing the
streams and rivers of North America in the 19th century, the kind of
vessel well-known from classic western movies.
These steamboats did not require docks or other harbour facilities for
landing. In fact, they had extremely flat hulls with a very small
gauge, so they could come very close to a river shore to moor there.
This was very common, and old photographs show that even important
river harbours (like St. Louis on the Missouri in the 1850s) did not
have docks or quays for the large number of steamboats landing and
leaving, since using the shoreline was much cheaper and considered
fully sufficient. Passengers could embark and disembark by walking
over long gangways, bridging the sometimes quite wide gap between the
ship and the dry ground. Cargo was brought on and off board by
derricks and on-board cranes. Of course, some large harbors did have
fully developed harbour facilities, and they became more common when
modern river traffic - especially for cargo - required more
sophisticated, efficient equipment. But this was a process which took
several decades.
Because they were equipped with low-going hulls, cranes and gangways,
these steamboats were able to land virtually anywhere as long as the
waters near the shore were at least as deep as approximately two to
two and a half feet (about 0.60 to 0.79 centimetres).
When such a steamboat had to stop, the engine’s ‘reverse gear’ was
used. Stopping feeding the boilers with fuel (most commonly wood, not
coal) had taken too much time before any effect had occured; also, the
river’s current might have moved the vessel while the engine was
slowly loosing power. Running the paddle-wheels (on both sides of the
vessel or at its stern) for a short time, however, brought the boat to
full stop rather quickly. Then, they were navigated to the shore for
mooring with low speed.

I acquired this information from:
Paul O’Neil: Der Wilde Westen - Die Flußdampfer. Time Life Bücher
1995, ISBN 90-6182-534-2 (The German edition of a book from a Time
Life series on the Wild West).

I hope this is what you were looking for!
Regards,
Scriptor

Answered my question completely and thoroughly; thanks.