Okay so if the lower hull/pod IS accessible, why would the access be limited to some two-meter (?) thick pylons?
If the ship was designed to be crew-accessible down there, why would it be designed with only thin pylon tube access?
I mean, there would have to be some design reason for NOT installing convention "interconnecting dorsal" or "neck" or similar Constitution-type structure.
Why would it be designed with severely limited physical access, if people were required to move between hulls?
Exactly. it would make no sense.

When in doubt, go with what seems to make the best sense. The overall Oberth design seems to me to be a cheaper, highly modular unit compared to larger workhorses like the Excelsior or Miranda.
I wish it was bigger, it's only 2 3/4" long.