Is it possible to move the cursor without repositioning the screen?

It looks like you're right, goto_oid() does seem to scroll the target oid into view when called.

If you want to do some operation on another part of the document without the user seeing the cursor jump around, you might be able to use doc_update_display() to temporarily stop screen updates while your script is busy. As long as your script doesn't take too long to run, it should be OK. You could try something like this:

function remoteOperation(targetoid) {
 # store current position
 local oid = oid_caret();
 local pos = oid_caret_pos();
 # disable screen updates
 doc_update_display(current_doc(),0);
 # go to target location and do whatever we need to do
 goto_oid(targetoid);
 do_some_stuff();
 # return to original caret location
 goto_oid(oid, pos);
 # reactivate screen updates
 doc_update_display(current_doc(),1);
}