Can you give more information on your plans?
As asked above:
Will the kids always be with you? Or just some of the time?
How often do you plan on using the RV and for how long each trip?
Do you plan on going sightseeing in multiple places or camping in one place each trip?
Do you plan on staying at public campgrounds (federal and state, BOR, COE, etc.) or private RV Parks?
The answers to these will have a bearing on what will work. For example, if you are only going to have the kids for 1 week each year, but you will be sightseeing every month as a couple and staying at private RV Parks, then adding a tent won't likely work (many RV Parks don't allow tents), so you'll want at least convertible beds (dinette, sofa) for the kids but a bunk model would be wasted space foe the rest of the time.
I would start by looking at different floorplans out there. Then just daydream about your typical trip idea with that layout. Can you see it working with the kids? Can you envision a bottleneck at mealtime? It is amazing what you can work out without ever setting inside an RV if you think about it.