The products we recommend here all used in our minivan camper conversion as well as any RV. We will add products as we think of things that may be useful to you.
For securing the couch/bed frame in our minivan camper conversion, we use ratchet straps, which attach to the seat brackets in the floor of the minivan. Some brackets are open such as the old Chrysler models with removable seats, and are easy to hook onto. For fold down seats, you may have to let the strap go down along side the trap door and hook onto something under the floor in the seat well. The frame of the couch/bed will have several places to secure the other end of the straps. When you get everything in place, you simply use the ratchets to tighten it down. For the bench seat belts, the best thing is to buy a set of “retro-fit” seat belts (available at any auto store) to match the van. They will have a bracket on each end to bolt them to something. You can use one of those oval chain links available at any hardware store with the screw-together coupling on them, so that they make a complete circle. Attach them in the same manner that you secured the straps for the frame of the couch/bed. At the upper end there will be holes in the seat to feed the buckles through.
You could also use eye bolts in the framework in some cases and possibly use turnbuckles instead of ratchet straps, but you MUST secure the couch/bed frame to the floor of the van… somehow!
A ratchet strap is also used to secure the additional cabinet that covers the porta-potty and has the microwave at the top of it. That cabinet sets behind the driver’s seat. This third strap goes through the cabinet just above the porta-potty opening, and is secured under the front (driver’s) seat as well as to the frame of the couch/bed. When all is in place properly, and tightened down, the cabinet will not move!
The microwave is also secured with a fourth ratchet strap over the top from side to side. That holds it secure to the cabinet, but it is easily removable if you decide to take it outside to cook.
That’s the nice thing about our concept van, is that you have choices! Too many of the van conversion companies try to mount everything in place permanently, and then you end up standing on your head to use it or twisting sideways from a sitting position and throw your back out! No thanks! I’m done being a contortionist for these engineers! I want to place stuff where it works for ME!
You can use bungees to secure other things for travel, like to hold the coffee maker in it’s opening. There will be a removable front on the couch/bed under the seat, and you can raise the seat to get to the storage under it, and/or remove the front panel to slide longer things out if you need to.
Heavy-duty spring clamps come in handy for a lot of things, and we always keep several on hand. If you use my suggestion in the ebook for mounting a bow-tie antenna, it would be on a 1/4-inch aluminum plate that you could secure to your roof rack when parked. If you use a rear tent, you can secure the part that covers your minivan with them. You can secure a table cloth with them. Believe me, you WILL use them… somewhere!