Everybody Poops!

Jokes aside, during the early design phase of Vandalf, our first camper, it became clear very quickly that family happiness depended, at least in part, on making restroom use convenient for my ladies. This was a point simply not worth arguing or trying to game. For the van, I ended up building a cabinet that was large enough to hold a 5-gallon Porta-potti. (Either the Dometic 976 or Thetford Model 365 - we ended up with the Dometic.) This style of toilet has worked well enough for our needs - while not a joy to service, the process isn't terrible and fits better with the "weekenders and occasional long trip" usage pattern versus a composting style toilet. Given where we live in San Diego, a traditional RV black water system was out of the question - the nearest dump station is 30 minutes in the opposite direction from where we usually adventure, which would add at least an hour of overhead to the end of every trip. 👎(Hard pass.)

While we were shopping Hawk Flatbed campers, we generally figured we'd opt for the cassette toilet option, but when this previously-owned unit popped up without that option, it turned out not to be a deal-breaker.  Our Hawk's original owners had made all their option decisions around maximizing storage. The indoor shower has a few plumbing bits that eat into the under-dinette storage, so that option was skipped. There's a similar story with the cassette toilet - the Four Wheel Camper system takes over that entire curbside/forward cabinet, save for the space consumed by the water tank and battery bank. 

Four Wheel Campers Optional Cassette Toilet (photo from FWC website)

Instead, our Hawk came with a split cabinet - an upper section with a flip up lid that should be perfectly suited to dry-goods and kitchen storage, and a lower cabinet sized for a porta-potti. Overall, this is probably a better solution, given that we seem to have been doing just fine with portable toilets thus far.

That said, there were a couple of minor problems:

1. The cabinet door opened towards the center of the camper - this is convenient if you want to fetch an item from outside the camper, but is 100% backwards if you want to take a porta-potti out of the cabinet while standing inside the camper - the door is right in the way.
2. The camper cabinet includes a 2" face frame around the opening - so in order to pull the toilet out for use, you'd have to reach in and lift ~40lbs up over that 2" threshold
3. Also, while the cabinet space is large enough to accommodate any of the 5+ gallon portable toilets, the face frame means the opening was just a hair's-breadth shy of being big enough to accept the taller Thetford "Curve" model toilet.  This toilet sits closer to a normal height and is thus much more comfortable to use, so it's the model we really wanted.
4. There are also some obstructions inside the cabinet - namely an aluminum wire channel at the back, and one of the bolt-down plates for mounting the camper to the flatbed.

I could kick myself for not snapping a photo of the cabinet as-built! Here's the cabinet with the door removed, with the original hinges mounted on the left side:

In order to solve all these issues, a couple of changes were needed:

1) I cut out the lower portion of the face frame (and removed a couple of the L-brackets that screwed it to the floor. These were relocated.)

2) I also needed to raise up the floor here slightly so that there wasn't a "Lip" due to the nice vinyl floor the previous owner had installed. I used leftovers from the same slippery polyethylene sheet I used to slide the toilet out of the Astro camper. You can see where I had to notch around the bolt-down plate.

3) Because the width of the Thetford Curve just barely fits into the depth of this cabinet, and it would interfere on that wiring channel, I needed a way to get the toilet raised up a little so that the base was above that channel. I purchased the marine "hold down" kit for the Curve and fabbed an aluminum plate to mount it to. This gave me a way to attach some one-inch feet to the toilet bottom without risking punctures. With the furniture sliders, even with a full tank, it moves nice and easy. (The wonky placement of the one foot is to clear the bolt-down plate and bolt head in that corner.)

With all of the stack-up, the Curve now fits in the cabinet depth, and the base floats just above the wiring chase:

But you can see it's a very tight fit:

4) Finally, I re-mounted the hinges and catch plate to reverse the swing of the door. I've got some color codes that should be a decent match to the Dovetail Grey finish to touch-up the old screw holes, etc.

I had originally intended to mount the removed-section of the face frame to the back of the door, so that it hid the gap and opened with the door, but it would have run into on that other bit of wiring channel at the entry threshold, so instead I will eventually fit a bit of felt or other semi-stiff filler that hides the gap but is flexible.