Yes a meat thermometer stuck into the center at 165-185f will do the trick. As for time that will depend on how thick you make the loaf. The smaller the pan and the thicker the loaf the longer it will take. a Large pan with a thiner loaf the quicker it will cook.
Its is quite easy to see if its done, when it starts to bubble clear liquid fat Not water around the edges and starts to shrink and pull away from the pan a little bit its getting really near done. The finishing temp is not to critical once its over 165F as its ground beef not a solid hunk of meat. You can also check the very center of the loaf by pressing on the surface of the loaf to make sure it has a firm feel to it.