To each his own, but I feel that pretty much ALL of the so-called benefits of a pass-through are little more than fancy excuses to justify one.
And for most applications, there are far more logistical drawbacks to a pass-thru than actual benefits.
I admit, when designing our camper, I really entertained the thought of a pass-thru.
But in the end I came to my senses. And never do we wish we had one.
Ours is a custom truck camper though.
With a legit integrated camper, especially a cab-over design, it can work well.
When I was in the design phase I was determined to have a pass through no matter what, for reasons that I can't remember now but it might have been for our dog who has been gone a long time now.
The pass through was going to be complex, my camper has a lifting roof with hard sides that fall into the pass through space and making it well sealed against the elements was not going to be simple so it was delayed,......for ever.
During the construction we used the rig and after many years I saw that for me it wasn't going to be needed, from "I have to have one" to "I don't want one" came about.
There are pros and cons to everything you cram into a rig and eventually the things that are important to you will rise to the top, pick your battles! So a good pro-con list is needed:
Pro: - Stay out of the weather entering camper.
-Get into cab from camper without going outside. For whatever reasons.
-Can access toilet, kitchen, fridge etc while driving.(passenger only)
- Sense of security.
-Makes a hole in camper. This was a big one for me, that hole into the cab would be right where the bed is and our camper is well insulated with double glazed windows etc and a big hole into a single pane windowed cab that gets hot in the summer and cold in the winter made no sense, I know a plug can be used or an insulated door but in a tight camper where do you keep the plug and how much swing space does the door take?
-Crawl through gets old fast.
- Walk through is better, but, you need a big rig for that, I went to great effort to keep my rig small which is much harder than going big.
-Lose a wall in a small camper.
-Both camper and cab structural strength compromised.
Well there is a start to the list, I'm sure others can add to it and as previously said the rig is yours and whatever YOU want to have is up to YOU but everything becomes a compromise in the end, you cant have everything!
To me, a pass through is what makes an camper and vehicle integrated in addition to the more permanent nature of the mounting system. Not all pass throughs are created equal either. Some allow for effortless connection to the living area like in a converted van and others are just barely large enough to reach a hand through for a chilled beverage in the back seat cooler. Having one has all sorts of benefits. Done well, It can allow you to have a shorter vehicle in many cases as pets may travel comfortably in that location instead of having an extended or crew cab. It can allow you and/or your passenger easy passage to or from the living area when weather is bad, or other outside deteriorating situations. It's easy to go from camp mode to drive mode and vice versa when the situation arises. It's easier to leave everything in its place so you don't have to transfer things back and forth as everything is easily accessible. I find Pass throughs as more essential when traveling in more populated and unfamiliar areas.
For Pass throughs to be effective they need to be large. Like in a van they're large enough to swivel seats and you can essentially walkthrough the space. The cab space doubles as living space and the converse is true as well, so you can get away with a shorter vehicle. The downside is the cab usually needs insulation as the large window is likely going to be the greatest source of heat transfer. Being able to secure the pass through is advisable for RoRo travel where others have keys to your vehicle and consequently all of the contents in the living quarters. (ed: same goes if dropping the vehicle off for service / repairs, etc.)
Is a pass through essential? Of course not. Most of the time when camping, the whole reason is to spend more time outside. Setting up camp is just part of the process. When traveling with pets, they usually need to get outside time when pulling in to camp regardless of weather. If you plan to use the vehicle without the living quarters, the passthrough portion of the truck may be bit awkward if poorly designed. All of this said, I do wish more truck camper manufacturers would offer a true pass through as it's really only available in builds of ~$300K+.