According to Ignoramus19325 :
I recently bought (for $50, non working condition) and fixed up a
little a used 10 HP Sears Craftsman garden tractor.

It is relatively heavy. Maybe 300 lbs or so. With me on it, it would
be 475 lbs.

Sometimes I need to move heavy things. Can I use this tractor to help
them move along? Is the transmission/drive/engine designed for that?

I have a 12HP hydrostatic Cub Cadet that's over 30 years old. We routinely
use it to pull around a 4x8 trailer (500 pounds _empty_) and whatever
we've put in it. We've probably pulled well over a ton total upon
occasion.

The trick is to be _careful_, particularly of engine loading and hills -
both the up and down, and watch your tongue (of the tractor that is! ;-)
loading!

While our tractor is considerably beefier than a 10HP Sears (weighs nearly
double I think), with caution, they can do quite a bit. But neither the
traction nor brakes are all that good, and with a heavy load, you won't
be able to go up hills, nor stop going down.

The only time I stall the tractor is when I try to take too big a bite
with the snow blower ;-)

As a related thought, do they take snow plowing attachments?

Yes.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.