Firstly, as Alastair has noted, living on a boat will be a total culture change and involve minimalism in a lot of aspects of life. Even in the best of weather, some of it will seem like camping and roughing it, toilet emptying being just one. Be sure, then double sure about this. I imagine embarking on a PhD but dreading returning to a damp boat at night could have a detrimental effect on someone's ability to study.
A mooring with 240v electric hookup is a bit of a game-changer in your post. You mention 12v only but then say the mooring has electricity and residential. An off grid vessel for travel becomes a floating outbuilding if it's on a hookup, and lots of us keep a freezer in the garage.
What type of heating does it have? Is hot water created by running the engine, is it a separate diesel unit, gas heater, hot air or combination?
Things like a freezer can be run off an electric hookup, just like having a big extension lead to dry land, when moored up but when the boat's not on the mooring, the power for those appliances will need to come from the batteries. Some people have incredible battery banks, do a lot of miles (charging batteries) and have a lot of solar panels and even they have to be frugal with their energy use if they are constantly cruising or have no hookup on their mooring.
I remember a young guy living on a 20' yacht you couldn't stand up in but he had hookup to it and the marina had a launderette and showers. He was quite capable of holding down a decent IT job.
You will come across boats that have been used residentially in marinas where the engine hasn't been run for ages because all power is drawn from the bollard and not the battery bank. Do make sure that whatever you are looking at has a decent engine. Big GRP river boats can be near worthless if old and tired and the engine needs replacing. You may not plan to use the engine much but starting with a good one and keeping it in good condition will protect your investment when it comes to resale value. Need not be anything wrong with well maintained, older engines.