Hi Deadman1020,
the answer is yes. you can stay completely in zbrush to do everything what you need.
but - and this is a huge but.
zbrush is a tool - a very powerful one.
like maya, blender, softimage, autocad, photoshop etc.
every one of them can be used to achieve a goal.
you could use autocad to create a character model somehow or a sculpting
tool to do cad works.
if that makes sense or if it´s wise - that´s another story - and a question of personal taste.
try to think about it this way:
you can user a hammer to insert a nail into a wall.
and a cordless screwdriver to drill a hole.
on the other hand - if you take the hammer and hit a board long enough you will
also get the hole or use the screwdriver to hammer a nail into a wall.
that´s unconventional but it might lead you to your goal.
it´s all a question of personal preference which tool you choose.
but from my point of view - if you choose zbrush to work with for modeling & painting and all
that is corresponding - zbrush is the best tool i would recommend.
the start is hard - no - better: different than learning other tools
but you won´t be disappointed.
and if you say you are having fun with zbrush - that´s the most important thing in the beginning
-> then the rest comes automatically.
there´s zbrush classroom with free tutorials - there´s everything you need.
good luck hope to see some work of you
cosmic