This will be a cut and paste from the link listed, it's how I feel about what I like in a conversion.http://www.busconversions.com/bbs/index.php?topic=3443.msg31162;topicseen#msg31162
I don't know what my dream coach would be like; I think my ideas would change over time as my needs changed. But, I do have some likes and dislikes.
I do not like the walk through bathrooms; my coach has a small bathroom with a door. There is enough room for one to do the three S's and change cloths. That leaves the back accessible; with a family of eight, that is important. One neat feature is that the door will swing open and block the front from the bath and the bedroom so that area can be blocked off if needed. Keep it functional, but where you spend the least amount of time dedicate the least amount of space.
Another feature I see that I don't like are kitchens that are too large. Plan on what you need and then cut that in half. So many builders get a grand idea that they are going to become a chef and overbuild and waste that area, never using it as planned. When we are on vacation, we don't have the time to make large complicated meals, and when we do, we like to do it outdoors. I have seen some coaches that have slide out kitchens in a bay. I like camp cooking, and we usually do it outside with Dutch ovens. My wife says she cooks enough as it is and vacation is a vacation from cooking for her. I understand that full timers might cook more, but I still think large kitchen areas are a lousy use of space that could be better used elsewhere. The kitchen is a great place to be creative with the counter tops and cabinets. Slide-out or folding counter top prep areas would be a good example of efficient use of limited space.
If you put a dinette in, I feel it should be on the passenger side. The side with the dinette usually has the most windows (I like lots of windows), and if used while you travel it's nice not to have to look out over the other lanes of traffic and the gawkers, but instead, see the scenery as it lazily passes by. As a driver, the low dinette and windows makes it easier to see an area that is difficult to see anyways. In addition, if you are at a campground, you want to see your side of the campsite, not your neighbors.
Finally, dedicate the most space to where you spend the most time and don't overdo it. Some of the nicest coaches I see are simple, elegant, and practical. Some people don't like dual use areas, but when you have a crowd like I do, it is a necessity. I am going to make the rear bed convertible, a U shaped lounge in the day would give me two living areas so as the adults visit in the front; the children can watch a movie or play games in the back.
One of my favorite features of my bus is that it still has the back window. At the beach I go to, the camping sites are directly on the dunes overlooking the water; these sites are back in sites. I love waking up to the eastern sun as it rises above the water, bathing the interior with light, and seeing it all through that big rear window. One day, unless I can find replacement rubber for it (Luke doesn't have it), it will have to come out. That will be a very sad day.
Enough rambling from me now, have fun with your project.