Costs
Last time I looked the annual cost for a continuous cruising license was about £800 or £900 for a boat of around 50-60 ft, which is the most popular size for living aboard.
You have to add a couple of hundred a year for
insurance, and the possible costs incurred by renewing your boat safety certificate every 4 years (I think).
And they recommend you repaint the lower part of the boat (with blacking paint) every 2 or 3 years, and that can cost over 1000 a time. Plus odd things will break that are usually more costly to fix than their domestic equivalents.
You don't need to have a home mooring, but if you don't have one, the CRT rule is that you must move your boat every 14 days as a minimum (which seems to be more of a challenge in winter). I think the idea behind that rule was to prevent selfish people from stopping permanently and effectively blocking access to the most popular mooring spots.
There used to be rules about how far you had to move after the 14 day stopping period, and how soon you could return to your original place, but I think maybe they are less rigid in recent years. Certainly thousands of people live aboard on the London canals based on continuous cruising licences, and never move more than 20 miles
You are allowed to moor almost anywhere on the towpath side of the canal within the CRT managed waterways (there are some others), although the popular spots will have limits of a day or two max, and some even less.
But what appeals to me is the freedom to find a nice quiet spot in a quiet rural location and just park up there for a couple of weeks, completely free from any kind of challenge from parking wardens, local busybodies, or whatever.
My one reservation about motorhome wild camping is how I would cope with a nagging feeling that wherever I am parked, I am basically on a ticking clock and will have to move on in a day or two (and maybe even sooner), to avoid hassle or problems.
There does seem to be a very sad mindset in this country that people traveling in motorhomes or vans can't be tolerated in one place for very long, and must be moved on, regardless of whether they are causing an obstruction or nuisance.
On a boat you are free from that feeling (which may not bother many people anyway to be fair), and it is the main reason why- when I retire in a few years) - I will try living in a narrowboat in preference to a motorhome, at least to start with.