Question on Queen Post (Fan) Attic / Garage condition.

Hello all,

I currently have a Queen Post (Fan) attic condition that utilizes 2X4" stud=
s, 24" O.C. and span approximately 19'10" across my garage.  I want to inst=
all an attic stair and be able to do additional lighting, and eventually sw=
itch the truss to more of a queen truss roof condition.

That being said, is it safe to walk from truss to truss?  (I will disperse =
my weight as much as I can utilizing plywood and other means, but just want=
 to confirm my weight (190) will be okay... Even if I put it all on one joi=
st?

Let me know your thoughts and appreciate any help / advice you can give!  T=
hank you all.

Sincerely,
Kevin