I really don't see an issue with the rooflines. Looks like the angles are fairly similar and the clean lines of both structures should be easy to coordinate, especially in your open, rural setting. Since you've found a stunning deal, I would say, go for it! I definitely would want to find an architect ASAP and by all means, before you pour the slab, make sure you have a plan to coordinate.

Wow, that was awesome Mark, thanks for that and everyone else. I thought about the desk facing the other way actually, to avoid feeling enclosed I do have really great views there so I thought about a small couch and maybe a bookshelf on the back, but having the dining table in front is probably not the best either.... complicated :( Here are a couple more pics, today was a beautiful day so I managed to get more of the views

Thanks , thats very nice. I like that style a lot. I found that Lighting Direct have these long industrial style ones which suited perfectly for going over a mirror cabinet and you can add an industrial style LED bulb. So Euro that have a Trade Me store sell nice pendants and decided to go with these for the 2nd bathroom.

To a fair degree , its not too bad , coming off the dining , but conversely I understand why its not ideal . As the plan seems to say 'final' , I assume it is locked in and you definitely don't want to move any external walls . The only other option I can see would be to move the door to Bed 2 to the 'right' on your plan ( to the inner end of the Bed 2 WR ) , and have the door to the Master entering from this longer hallway into what is now the WIR . If you went down that route , you could either rearrange the ensuite and WIR and have a hallway , but the other option would be maybe 4 or even 6 doors and a non-walk-in robe along the wall that currently has door . Thinking , you could even walk through the WIR I guess , but that would be at the bottom of my preferences .