There is a minor error in the descr_strat file which makes the wool resource in the Edinburgh region inaccessible to a merchant. It's not important, but anyone playing England or Scotland might want to fix it. Here's how:

Find the descr_strat file. BACK IT UP in case you mess up! Copy the file and then rename one to descr_strat - copy, for example. Open the descr_strat file using any text editor, even vanilla notepad, and find the following line:

resource wool 99 309 ;Edinburgh

Change it to:

resource wool 99 310 ;Edinburgh

This moves the resource up one space on the map, allowing the merchant to be placed on it properly. You can move it elsewhere, but one space is all that is needed and keeps it in easy view (i.e. not hidden in trees).

If you wish, you can also correct the duplicate descr_strat files located in

Medieval II Total War/mods/tlr/data/world/world/maps/campaign/imperial_campaign
Medieval II Total War/mods/tlr/data/world/world/maps/campaign/norman_prologue