Hi!
KNK have some nice stuff in, can be a little dear though? Might be me though........a few folk on here have used them i think, but ask plenty of questions, get plenty of photo's if you are buying a little blind - common stuff really.
Ask around some of the traders on here, Midland Early Bay, Gadget Boy etc are a couple off my head, best thing to do is have a look at the for sale section to get a idea of what is currently available, and the price, from dealers and private sales. You'll see stock buses and modded ones, the price will vary depending on LHD and RHD, tintop, poptop etc. As you are just looking for a standard microbus, these are normally cheaper to buy, you could get a solid LHD microbus needing no welding for maybe 5k ish (might be less or more depending on condition) You could add some camping stuff like RNR bed, or Z hinges to stock microbus seats if you want to camp away.
As for mods, well so much out there, some folk like stock, nice and simple, but a lowered bus with nice alloys does look the biz, but i like the stock height, and the floaty ride! Horses for courses! I like simples - but if money was more flush.......
Brakes? A stock system is up to the job, after all it's 40 years old, and not up to modern braking - I've a 70 Westy, so stock wide 5 wheels, drum brakes all round, no servo. It all works well, just plan ahead, it'll stop, I can lock my brakes up - just have to press hard (ok, very) but a servo would certainly help no end. You can get remote servo's of Ebay for a MGB for like about £80 ish.
A 71 onwards bus has disc brake front poss with servo, and the servo eases the pedal pressure, wouldn't necessarily stop any better, but may well resist fade. At the end of the day, appreciate the vans, and yours abilitys when it comes to brakes, and you will be fine. I have been up and down Porlock Hill, and Countisbury Hill, here in Devon/Somerset, and they are very steep at 25%, but just go slow - I used 1st for maximum braking on Porlock Hill, ignored the cars that overtook me down the hill, and chilled out, I ain't in no rush, and the brakes coped fine, no overheat, no fading - all long as the brakes are in good condition, something I would want doing on any van I bought, especially a import. Brake conversions such as CSP, or Futbus, or just a Porsche 944 turbo setup will work wonders.
Good luck in your quest!
Cheers!
Alistair