I'm a bit late back to the party, but my pen'orth for what it's worth...
Mudguards. Yes, I manage. But that is mainly due to that fact that for most of the time I've owned the trike, it was mudguards or eating, moneywise. I think a set is moving up my wishlist as the current account accumulates. I may see if MFWHTBAB will do me some nice laminate ones.... I find that I get dotted with spatters on my arms, rather than gathering a puddle, but the odd spatter gets my face, and while I'm not a fussy type, I'd rather not eat too much mud.
Also, it is more sociable for anyone you're riding with - an upright rider tucking in just to one side of the rear wheel could get a face full.
Tyres. I have Kojaks all round, and in 1800 miles odd, have had one flat, a nearside front, presumably from something I ran over in an urban York gutter (it was an instant deflation event). I thought it would be hell to get the tyre off, being a small wheel (16") and a 'racy' tyre, but in fact I found it very easy, perhaps the easiest of any I've done. Levers to get it off, but thumbs alone to get it back, unusual for me. They do roll beautifully. (I do appreciate that you're going for the 'no need to fix ever' option, as opposed to 'low risk', but I was very surprised at how easy I found the Kojaks.)
The lowish pressure/big tyres thing is a good point. My winter hack has Big Apples, and last winter, thanks to a bad back, my tyre pumping up regime went to pot for about 2 months. By the time I got round to it, they were down to 1 bar, and still rolling, without damage.
I think p*ncture rate can be moderated by riding technique. One of the guys I tour France with rides all his machines into the ground, and always comes top of the list in the group for flats. Along with bearings disintegrating, bits falling off etc. He does ride 1000s of miles, but he also seems hard on the machines.
Anyway, it's all very exciting!
