I'm not sure I would be able to do it, certainly with a camper, that is sure to eat up a huge part of your budget. Traveling the world is one thing, doing it on 4 wheels (or more) is quite another.
I would suggest to make a list of why specifically you want to do it on 4 wheels, and even more so with a camper, while balancing the advantages and disadvantages. Saving on accommodation will only work in the western world, not in the developing world.
Perhaps look also at alternative 4-wheel transport, like a small van with 4WD (like Subaro) or a jeep-annex-tent. Even with a motorbike, shipping and admin costs (carnet) can be steep, so with a 4-wheeled vehicle it could be prohibitive.
If you have all the time in the world, the easiest form of transport would certainly be a simple bicycle. No border restrictions, no driver's license restrictions, easy repair/replacement, etc. While in the beginning you might crawl along at 40-50 km per day, you'll gradually build strength for larger distances.
Actually, the slower you go, the more you get connected with the worlds you are traveling in. What you loose on speed/range, you win on experience. And if you ever get stuck, or just want to skip a certain part or country, it's never a big deal taking a bicycle on a flight, or bus or train trip.
If you set your priorities right, and manage to choose the right mode of transport for your budget, the dream could become a lot more achievable.