Having trouble building a RV garage beside a 2 car garage with a small house over it

[Jerrykco]

I am trying to build a RV Garage to the left of a two car garage. The RV Garage has walls 14' and the 2 car garage has 12'walls.

I added a 2 floor over the whole thing but really only want a floor over the RV garage so I get an attic room over the RV Garage.

That way I can have a large storage room in the Attic over the RV Garage.thats accessible from the small house over the 2 car garage.
There are several things I cant figure out.

I do not want 2ed story walls over the RV Garage but because I put s second story over the RV Garage now when I build a roof it actually cuts off the first story walls.

I also added a 2ed story with walls over the 2 car garage for the house and a third story over that without alls incase I needed a stairwell over the small starrs to get into the bous room over the RV Garage.

I have attached a plan as stated above and a picture of the roof I wanted however this picture is from a plan that has no floor over the RV Garage only the ceiling. (the roof is good but I couldn't get to the bonus room in the attic over the RV Garage. )

If someone cares to take a look and tell me what to do I would appreciate it. I am a novice but like to learn. 

RV Garage Plus 2 car garage under 2ed floor house over the 2 car garage-3.plan

[solver]

Start a new plan drawing a rectangular space, then divide it with a wall so you have 2 rooms similar to your garage.

Set the ceiling heights of the 2 rooms to 12' and 14'.

Build a 2nd floor like this.

 

Now on the 2nd floor, open the room over the taller side and reduce the ceiling height.

[Jerrykco]

Thanks Solver. I will give it a try. I have already tried three times.once more I home does it.

 

[Jerrykco]

HI Eric,

I was able to build the plan from your suggestions (build a second floor and reduce the ceilings) but ran into another issue.

I reduced the 2ed floor ceiling to that of the first floor height. I looked OK but then when I added a door into the bonus room I was faced with a brick wall.

I was able to delete it bu placing a camera into the bonus room and and clicking on the wall (it was labeled an attic wall.

Is that the correct way?

Also I really want the second floor wall that faces the west to be a full gable so the west wall eliminates the hip roof (shaded) in the picture.

What is the proper procedure to do that?