Here is the sketch

O.K. I'll bite. On the Scenic Ridge layout where the two tracks go to the new addition is the upper track 4 inches higher than the lower track? If it is you don't seem to have a problem as you have plenty of distance from point A to point B to gain the elevation with no more than a 2 to 3% grade. My biggest problem with it would be there are no switching areas (I like to operate), but if that's O.K. with you I guess you are good to go.
 
I agree with Tyson, I think I would use the extension for some switching, but that is just me. Other than that, I like it and it looks like it would be fun.
 
What are the dimensions of this plan?
Is it a 12" grid?
If it is, I'd say you're going ti need some access hatches in there to get to all the track.
Other than that, it looks like it would be great fun to run trains on!
 
...so I'm presuming this is N scale?
If you're interested, I'm trying to hash out a walk-in style plan for expanding my N scale K&I RR.
You'll find it in the Track Planning For The Future forum. The thread is titled Another K&I Expansion Plan.
The drawings are kinda primitive, 'cause I don't have any cool track planning software...I'm still operating in the stone age with ruler, compass, & graph paper.:rolleyes: But take a look anyway, it might give you an idea, or two. :)
 
2 % or 3 % grade

Bha, 2 or 3 percent grade, hell when I build my layout its going to have a loop like a roller coaster. :) Although that's an interesting idea, modeling a roller coaster.