Shorter length 'self supported' races

Try the Valleycat: http://www.valleycat.cc/

Not sure when the next one is, but it's put on by the people who organise the TCR as sort of a taster. I listened to a really interesting Bike Show podcast about it (http://thebikeshow.net/tag/valleycat/).

The description on the Valleycat website is as follows:

"Valleycat is a cross breed of the Alleycat and the traditional Brevet.  A long distance self guided ride over one or more days collecting images at strategically placed passive controls.

Control locations are spread out across Mid Wales and are released at the start of the event.  Riders must choose how much planning time to allocate before getting out there and putting miles on the board.

Plot a straight route cross country in Wales and you'll be guaranteed to find some hard gradients.  Around here you will find some of the most brutal in the country.  Go around and it may take you longer.

Ride alone or with friends.  Its not a race, its a game."

Even on TCR-type events, as far as I can see you're basically racing yourself to the finish and then you find out how many people were faster than you.  So audax-type events are ideal - you can complete them as fast or slow as you are able.  Or you could set your own challenge - after all unless you're riding on closed roads it's just a bike ride.

Have a look at some of the British ITTs such as Highland Trail 550 (Scotland), BB200 (Wales). These are challenging events over challenging terrain.

Have a crack at the NC500? 

http://www.northcoast500.com

The site of which seems to have turned into some sort of weird paid-up private men's club. Not sure what all the exclusivity nonsense is about. Guess they're trying to get tourists to drive cars in a circle or something. 

Anyway, ignore that, take a look at the map and try not to die in the weather, because from here until late Spring, that area will be nothing like the pictures they're showing on site 

Have a look at the audax.uk event calendar. Loads of rides over 200km on there (perhaps not at this time of year though).

Oh and, not races. I'm in awe of anyone who has the mentality for the extremes of endurance riding but with (perhaps) the exception of things like the headline events like the Trans Continental and RAAM they're more personal challenges (partly because if you start racing them cost rockets with liability insurance).

Try audax. Events of 200, 300, 400, 600, 1000km and more.

Definitely not races though.