We have a 350TS on order and had many of the same questions as you regarding options and such. The posts that the members of this forum made were invaluable in making many of our decisions. The link to this post is
What are the best options to get?
One of the things that was important to us is the number of seat belts. US regulations prevent the installation of more than 6 belts in this unit. If you request it you can get one more in Canada due to the different regulations. We actually wanted 8 belts and I am trying to figure out a way to make it happen.
I also had questions about the drivers door. Most of the units ship without it and the FR rep did not even have a picture of one. Many of the people who had the door were not enthusiastic about it and felt it difficult to use and perhaps even a safety hazard. In the end I did not order the door.
The opinions I got about double pane windows were almost all positive. I am hoping to take ours on few ski weekends and felt they would make the unit more comfortable and easier to heat especially if we end up north of Quebec city at Le Masif in February.
Apparently the kitchen exhaust fan is a recirculating type (which IMHO is not an exhaust fan) so I would recommend the fantastic fan options.
Best of luck with your choices. This is a new experience for us as well and we are quite excited about it. Keep in mind that my opinions are based on other opinions and not my own experience with the 350TS.