[Don't worry about being confused. What you need to worry about is the so-called experts who are often just as confused but charge you big money to provide you with an inadequate system]
It comes down to a couple of things - what sort of lifestyle you want and how much you want to pay to (try to) achieve that.
By lifestyle, I also mean whether you ever free camp and for how many days, how often you use powered sites, how many hours you drive, whether you would want to use a generator and of course what sort of electrical load you have installed. A few years ago a typical van had one light in the middle of the roof, maybe a reading light if it was a bit up-market - and very little else. Nowadays there are general and task lights installed everywhere, outside flood-lighting, heating and cooling systems, a couple of computers, a couple of water pumps, 220 Litre 24V compressor fridge, large entertainment systems, satellite systems, microwave ovens, washing machines and even bread-makers and espresso coffee machines. I haven't got the last two, but do have all the others and more, and in sunny Australia can use all this without concern for running out of power, and do it indefinitely. The only limitation is the amount of water and black and grey water we carry. My generator was last used in anger over 12 months ago while in Tasmania where is never seems to be able to make its mind up what season it is.
This doesn't come cheaply - 4 24V 165W (I think)
solar panels and a 24V 520Ah AGB
battery plus all the electronics that goes with it, but it does prove that
solar is practical provided you have enough room and load capacity to fit everything. My batteries weigh nearly 400Kg so it's not a trivial consideration. We are full-timing so the criteria are way different to those applying for just one 2-week holiday plus the occasional weekend.
In the north of Europe (Norway, Sweden, ... - even in the summer, with panels laid flat on the roof you could expect maybe only 1/4 of the rated panel output so then a small generator might be more useful if you are going for any extended wild-camping in one spot.
The MH we are buying in Amsterdam won't have any
solar fitted - but is being fitted with a 40kg refillable gas cylinder (hang the expense or the legality) - so my first job might be to find a quiet spot and stick a couple of panels to the roof. They may not provide all my requirements but from the stories told of shonky campground electrical hookups, I figure every night we can do without will be a bonus.
-----------------------
The tracking
solar panels ARE 5 times more efficient than the same size panel mounted flat- BUT only if you do your test somewhere close to the Arctic circle. Otherwise they are just an expensive bit of poseur bling just begging to be wiped off the first time you forget to stow it.