I usually hit it with some 150/200 if the surface is in good condition [like you have already stated]. If in poor condition, rougher grit, working your way to a higher grit. After you do a shot with 150/200 grit, you may want to go over it with some 300 grit.. if you are very picky, and want this sucker to shine like no tomorrow
. As a rule of thumb, if you aren't going to wet sand it, it will be a waste of time to do more than 200 grit on an initial sanding.
For those tight to reach places, try your best to get to them. Fold the sandpaper real thin, so you can really work it into there. Sometimes putting on a square cm [or .5 sq inch] of sandpaper on the tip of a medium sized flat screwdriver to help work it in there, will do wonders. Be sure to be careful when painting in those areas, so you do not have a build up, or runs. You'll have to start all over with that.
You may want to consider doing this.. if you plan on wetsanding [otherwise, ignore]. After you spray on a beautiful coat, to just lightly go over it with some 300 grit, and sand it until dull [after the paint dries overnight, of course]. Then repaint again. This usually gives a deeper colour, and gives more paint on the surface for you to wetsand [to get the ultra smooth paint].
Don't forget to use rubbing alcohol after sanding, to clean off any dust/material. This way the paint sticks to nothing but the item you want painted