Garage office Power Venter install help

Hello,
I just got a great deal on a 3 year old Leisure Line Econo that has only seen .5 ton of coal thru it. But I'm really restricted on where I can install. I have an elevated office in a 2 bay garage. The 2 exterior walls in the office have large windows within 7' of each other. Also an overhanging roof closer then 1' to the top... If I understand the power venter instruction correctly I can't use it on either of these walls. This leaves me the other option of mounting the stove on an interior wall and across the ceiling of the garage. doing the following:
out bottom 4" 90 up then 4" 9'-9" vertical pipe, 4" 90 to wall, 3' Horazontal pipe thru wall (with proper pass thru), 4" 45, (to adjust angle) 2 more ft of 4" , another 45 elbow and then 15' of horazontal to the power vent located high on the bay side wall near (2') a large exhaust ventalation Fan. I would have to hang all of this pipe from the 12'-6" ceiling. There are bedrooms above this garage.

Questions
1) have others run this much horazontal pipe to there power vents
2) if the stove were chugging away and the hoz ceiling pipe somehow became dislodged would the Econo shut down without killing the people living on the upper level?
3) is this trouble worth the effort when I can get a pellet stove (with less BTUs) and pipe it between my outdoor windows
4) Is there any way to reduce the clearence of the PV to 3' to windows? if so It would be a simple install , Building inspector already told me he dosn't like the idea of screwing the window shut, would want me to remove it.. thats not happening. THanks alot for your help

It would help a lot if you could post some pictures or a drawing or two of what you have & what you want to do, from what I'm getting from your discription you may just need some chimney pipe & do away with the power vent. With pictures there are people here that I'm sure could tell you better.

I wish i could install a stack but it would need to be really tall to reach over the 2nd story. I,m going to get a pellet stove, i would be worried about the cieling pipe running thru the garage.