Pros:
-More living space
-We both get to sleep by the window
-Space for the bench seat in front of the bed
Cons:
-Crawling over each other to get in bed
-Harder to level the bed while parking
-Less space for the dogs
-Less under-bed storage
Thoughts:
When I originally built out my Sprinter I had the bed set up this way as well. I could just fit, but soon realized that no one else would be comfortable that way (same went for the short top roof in the van). After a few trips with the perpendicular bed, I did some modifications and one of them was to make the bed run lengthwise. It cut into the living space, but I realized that most of the time spent in the van was sleeping, so everyone might as well be comfortable. The lengthwise bed worked out really well in the Sprinter.
When we got the Promaster, we figured that's how we would set up the bed as well. When we actually measured the interior space, we realized we would be able to fit across the van and our plans changed. Sleeping across the van would open up a lot more space for us, which would be helpful given the large size of the side sliding door (lengthwise would put the bed almost out to the edge of the door) and the fact that wanted to have more space for cooking and other activities.
So far it has been working out terrificly. It was a bit of an adjustment for Star and Titan who were used to having a bit wider of a bed and sleeping with a human or a wall on both sides of them. Now they sleep on the open edge of the bed so if they get nervous about sliding off they scoot really close and we sometimes get squashed together against the back doors. It is really nice that both humans can have their heads next to the window so we get fresh air all night. We've found that if we set our fan to suck air out of the van rather than blow it in at night, it pulls a nice breeze through the window.
The only downsides to the bed set up are that we have to crawl over each other to get into bed and that we have a lot less under-bed storage space. I could fit an incredible amount of stuff under the bed in the Sprinter because it extended out so far into the van. We are really happy with the storage we've designed in the new van though, and having the bench for storage in front of the bed really helps as well. One other thing I've noticed is that it's hard to get a level bed when sleeping this way. When your bed is lengthwise you can always park on a slight slope so that your head is elevated, but when you're sleeping sideways on an up or down slope you're going to be rolling off the bed or into the backdoors.
All in all, I'm really enjoying the new set up! If you are thinking about sleeping perpendicularly in your van, think about how much time you'll spend sleeping vs. how much time you'll use an extra 1-2 feet of space in the van. I think having a good, comfortable spot to sleep is incredibly important so I wouldn't jeopordize that for a bit more standing room. If you have a wide van or are on the shorter side though, I highly suggest it!
