decided to make this real quick add this to the bottom of your mapname.gsc file

location_display()
{
	players = get_players();
	for(i=0;i<players.size;i++)
		players[i] thread location_display_text();
}

location_display_text()
{
	hint_hud = create_simple_hud(self);
	hint_hud.alignX = "left";
	hint_hud.alignY = "top";
	hint_hud.horzAlign = "left";
	hint_hud.vertAlign = "top";
	hint_hud.fontscale = 2;
	hint_hud.color =  (1, .2, .2); 
	hint_hud.x = 2;
	hint_hud.y = 2;
	hint_hud.alpha = 1;
	text = "";
	while(1)
	{
		text = self get_location_text();
		hint_hud SetText( text );
		wait .1;
	}
}

get_location_text()
{
	text = "";
	zone_name = "";
	zkeys = GetArrayKeys( level.zones );
	for( z=0; z<zkeys.size; z++ )
	{
		zone = level.zones ];
		for (i = 0; i < zone.volumes.size; i++)
		{
			if (self IsTouching(zone.volumes[i]) )
				zone_name = zone.volumes[i].targetname;
		}
	}
 
	switch( zone_name )
	{
		case "start_zone":
			text = "Spawn Room";
			break;

		case "power":
			text = "Power Room";
			break;

		default:
			text = "zone not defined";
			break;
	}
 
	return text;
}

add
level thread location_display();
under
level thread DLC3_threadCalls2();
at the bottom of the main()
now how it worksat the bottom fuction of this ( get_location_text() ) theres this bit

	switch( zone_name )
	{
		case "start_zone":
			text = "Spawn Room";
			break;

		case "power":
			text = "Power Room";
			break;

		default:
			text = "zone not defined";
			break;
	}

this is just an example part ive added, for it to work in your map youwil need to modify this.
the part that says - case "start_zone"
this is the name you gave the zone in radiant
the part directly under it, the part that says "Spawn Room" is what will be displayed when your standing in this zone.
change the example ones to two different zones you have with a name you want to give them and for every other zone you have copy and paste this part and change it to be as you need it

		case "start_zone":
			text = "Spawn Room";
			break;

hope this is easy enough to understand,let me know if you have any issues

zone =  level.zones ];

zone = ( level.zones );