I bought the Anna Leigh from David about 6 years ago. I have found these modifications he did to work very effectively. At first I was disappointed that he had removed the marine head and replaced it with a porta-potti. I have since changed my mind! You can't beat the simplicity of the porti-potti....no pumps, no leaks, no smells, no clogs. But best of all, I like that I can just put the boat on the trailer and go home without having to go to a pump-out station. A quick dump into my septic tank; then a rinse, and the job is all done.
The diesel heater is a must up here in the NW. The heat it provides creates great comfort, but its best feature is the ability to keep thinks dry. The relative humidity is obviously lower in the cabin when the heater is running. So when you and your clothes are wet, there is a way to dry things out. All surfaces don't feel damp either. The counter top heater will do that too I assume, but it must be awkward to have that hot piece of metal right there, in the way, and being a hazard. I find 2 gallons of diesel last me a long, long time.
I too cook on one of those Asian $30 butane stoves. I find NO inconvenience at all. Unlike most folks, it seems, I do cook inside (not always tho). I like being able to put the stove where ever convenient -- it is sometimes on the counter, sometimes on the table, sometimes on the platform under the removable helm seat. It responds quickly and is instantly adjustable down to a very slow simmer. The only negative is when I have to boil lots of water (like for pasta or cooking crab).....it just doesn't have enough BTUs. For that I purchased a 10,000 BTU Coleman single burner that sits on top of a 1 pound propane cylinder (the propane is far cheaper than the butane too). I use that stove in the cockpit.
Like David, I would have a new boat setup this way too.....including an under the counter instant-hot instead of the water heater. In the cabinet that now houses the water heater, I would have them install a freezer.