OK, yes the thermostat is all the way at the bottom of that water cover. You can access it without removing the head if the screws will come loose (not a salty dog), but it is tight and tricky. The first thing to do is to remove that darn hood latch if you can get the bolt loose. The is a tedious process as well because the bolt backs out and hits the head, so you have to walk the lever out of the pan slowly while removing the bolt. It might also be helpful to loosen the two rear lower pan/mount bolts, one is under the left side of the head, the other is at the bottom of the exhaust cover. Again, don’t remove them completely, just loosen them up, or all the little mount washers will fall out of place. Once the mount screws are loose, you can wedge the pan downwards a bit for a little better access.
And yeah, best to remove that fuel line as well, it is probably stiff as a board and needs to be replaced anyway. Just be sure to get the new line in place before retightening the lower pan and reinstalling the hood latch.
Finally, from the looks of your picture, that cylinder head was never updated to the new style. No big deal as long as the owner isn’t planning on using the engine for fishing/trolling.
And yeah, these engines are an “aquired taste” when it comes to working on them for sure.
