I'm entertaining a similar idea - buying a motorhome. I live in the UK and not only are rents extremely high, but I have no hope in hell of affording even the deposit on a real house so I'm stuck between a rock and a hard place. A motorhome would offer me some nice options - I would own it outright and be able to customise it to my needs. I would get nothing back at the end of a rental contract, whereas should I decide to move out of a motorhome, I could sell it. I would have to sign long-term contracts for utilities and pay daily standing charges just for the privilege of having them routed to my house before I even used them, whereas I could just go buy a gas bottle and not pay any more once it's hooked up.

I could customise the interior of the van as much as I liked - pictures, posters, whatever. Electrical customising is particularly appealing - with all my stuff low-voltage, I could fit some solar panels to the roof, along with some deep-discharge batteries, and totally eliminate my need for mains electricity. Modern motorhomes come with the equivalent of central heating and combi-boilers so they're surprisingly warm and you have on-demand hot water for a shower. I'm sure boats could be the same. With a decent 4G modem and antenna, I might even get good enough internet access.

You say you can't invite people 'home', I disagree - some might share the enjoyment of being on a boat as much as you. Okay, if the boat is far too small, then yes, you do have a space restriction. You're also unlikely to be seen as a hobo, so long as you have a job. Over in the UK, I know a few people who live on houseboats. They're not given a hard time. In conversation, others express appreciation for the idea of living on a boat.

My main concern with the motorhome is sanitation - you'll likely face a similar issue on a boat. Chances are, you won't be able to flush your toilet straight into the river, so you'll end up emptying a chemical toilet on a regular basis. You'll also need to obtain drinking water from somewhere. Mains water and drainage are the major things I would miss. To get access to those, I'd need to look at leasing a pitch on a campsite long-term, although still easier to get out of than a flat rental. The rest of off-grid living is practical - solar electricity for low-voltage lighting, gas or diesel for heating, and the freedom to move away at a moment's notice.

In my mind, living mobile shouldn't be stigmatised. People forget that humans as a species were once highly nomadic. It's only since we invented the concept of land ownership that it's now seen as unacceptable to try to strike out on your own. The others bring up very good points about maintenance on a boat - be prepared for this. If you're going to stick to a river, you'll have freshwater, which ought to be less brutal on the boat than saltwater, but you've still got the other issues to deal with. Water is unstoppable and will get everywhere it can if you let it. Big concern for me with motorhomes is whether they're sufficiently weatherproof. Boats will be worse, but at least with a sailboat you don't have the concern of leaking propeller shafts deep in the hull that you can't get to.

Your best bet will be to take a short holiday on a boat and see how you like it. Some of my relatives did this recently as a family - one of my cousins was indifferent to it, the other fell in love with sailing and now knows what she wants to do with her life.