When taking pictures like the one in your first post, as you using a tripod, you can take more than one shot. Take on shot kind of the way you did, but trying to get the foreground as sharp as possible and have the focus set on the foreground. Then take another shot, but this time focus on the moon - and underexpose the whole frame. As the moon is very bright this will have you get a lot more details out of it (like in your second try). Then post process the whole thing, and put the two images together in e.g. Photoshop. You will then have a nice foreground to make the picture be more than just another shot of the moon, but at the same time have details showing on the moon as well.
What camera are you using? If you have one that supports Live View, this is very effective when focusing on the moon. Use Live View, zoom in on the screen and use manual focus to set it dead sharp on the moon. This will get you a very precise focus.
Here is my first try to shoot the moon after reading up on it a little bit. This was shot at 200mm, so you should be able to get even closer with your 300

This shot was adjusted little bit in Photoshop, but not much.
(hope you can see the image, as this is the first time I try to link to this host)