Family Van Tradeoffs

You didn't specify your tow vehicle. Please make sure you are fully informed about weights. For example where a twin cab ute claims 3.5 tonnes towing, that may only be true with no fuel in the tank and only the driver aboard. Ensure the total combination weight doesn't exceed you GCM as well. Better to sort it now than be put off the road at a weighbridge a long way from home.

Are you looking for new or second hand Kelb? Without getting into brands, I will make a few comments.

I agree on length, although with fixed bunks plus fixed bed for yourselves plus bathroom, 19' may be a bit of a tall ask.

A bathroom with separate toilet and shower cubicles bathroom may be convenient, but think of the space it takes up - further enlarging your caravan. A lot of space for use only during only a short part of the day. Go for a small combo and have more space for living. Use caravan park bathrooms when staying at these, using your own only for night visits and when camping out.

Cupboards are valuable, as you will have quite a load catering for your children and their interests. However there is a temptation to pack them and go over your ATM limit, and or your tow vehicle limit. Weights and appropriate tow vehicle are major considerations.

Many caravans have the space saving sideways bed. Again, this gives more room for living, or it saves you having a longer caravan by a couple of feet.

I am not familiar with The Adventurer (nor what brand the model you are referring to is) to know what you mean about the bunks being closed in. A curtain or method of closing the area would be needed for get the little ones to sleep if you want to stay up longer in the evenings.

With your shopping list provided, I think you should be able to tick everything off your list. Whilst not impossible, 19 feet is almost the minimum size for an ensuite rather than a combo. Wouldn't compromise on this with kids. We've reviewed many vans at shows and pretty well seen what you're after including island bed, club lounge, triple bunks so not sure you really need to compromise. I would think you can fit more in the van than the Swan, so you just need to look at clever ideas for hanging things etc. if you need more storage. Try to take things that have multiple uses. Just be mindful of your payload.

My neighbours had a 19ft concept ascot built for their family with triple bunks, island bed and ensuite approx. 5 years ago. They are happy with it.

If I may share some experiences:
1) bed size and orientation, inclusions etc: If you are considering the van for offroad purposes, then you will need to weigh up your preferences; as simple example, whislt we would have preferred an island bed, it was more important for us to have a van the same width as the car to fit through bush tracks and avoid the towing mirrors. Off-road ability then also impacted on the toilet shower combo, due to length and width.
2) 3 kids: We purposefully did not plan to have a van taylored for the kids; sure, in an emergency the van can cater for the three extra bodies, but most of the time (from age 7 or 8) they actually prefer to have their own tent as part of their camping experience. A simple 3 second popup tent was all we required. This suits us fine as now that they are older, they either bring friends (tents as well) or they don't come at all, so the van is still fine for us.

Hope this helps