Have just had a look at the Centurion Events - TP100 is 2 points, NDW100 is 4 points . As 4 is the maximum you'll never get more than that - no matter what the race, though I think something like The Spine / Dragon's Back should automatically qualify you
UTMB is 7 over 3 events I think, which means you HAVE to do at least a 3 or 4 pointer to qualify. From the various races I've done, 3 and 4 pointers are more than a "day out in the hills" and are definitely a step-up from the 40-50 milers that you can jog around in 7-8 hours!
A little off-topic - but Western States is tightening-up it's entry criteria from next year to 100k under 16 hours or a 100m finish in qualifying races only - it's nice to see LL100, WHW, TP100, NDW100 and SDW100 included in the list though...
As I currently have no ambition or desire to do UTMB or any of the associated races the points aren't of any relevance to me - however...
Where I have done races that have UTMB points, the number of points seems to reflect the difficulty of the course quite nicely, e.g. Fellsman = 3, Country to Capital = 1, NDW100 = 4 and the MCN One Day series are generally 2 each.
Having UTMB points also, (for me - rightly or wrongly) gives me the perception of a established and well organised race! I can't think of any that I've done where I've come away thinking "that was a shambles" - so, from an organisers perspective, the kudos of the UTMB logo may be worth it?
I say get on with it as long as you're either carrying enough food and water to keep you going, or know or resupply points. Coast path running at night is no more dangerous than any other type - and for me, better as long as I keep the sea on my left/right I'm on the right route! You'll probably find there are pubs / churches / WCs with outside taps en-route, but don't count on it... I often find myself in someone's garden filling water bottles from outside taps
I did the Adventuehub Exmoor coastal ultra route, (44 miles/9,000') last weekend solo, really enjoyed it - not being in a race takes the pressure off a bit and allows you to enjoy the day!