I used to own 2 luxury caravan sites in France and as I was still a "tugger" (caravanner), I had always poopooed the idea of owning a motorhome, but then we had several self built campervans come along and along with my own observations of hundreds of professionally built vans, I thought to myself, if I can't do far better than that myself etc. etc.
Some 4 years after I finished my conversion, we have toured very extensively around France and the UK and have loved every single minute of it, most especially as our LWB panel van conversion is so easy to drive almost everywhere, unlike so many professionally built vans that are simply far too big to drive!
As for the diesel scares, don't worry about it, there is so much smoke being put up........... what are they going to do, suddenly ban all HGV movements as well and as for your concerns about sites, join one of the big clubs, my own choice being the Caravan & Motorhome Club and stop on one of their truly brilliant CL sites in the UK and when it comes to going to France or Europe, make use of the truly excellent Aires where our 6 week long tour of France last year was all at Aires where our choice was made for us by selecting those that didn't levy any charges at all.
This is the inside of my self built 'Millie', oh and by the way, behind the big door is the loo/shower and the sofa makes up into a full sized bed in less than a minute. 5 of us sleep in her, that is me and my most beloved SWMBO + 3 spaniels.