I’ve done a few unsupported. I always took a tent for a good nights sleep the night before – this rarely happened as I was too busy “socialising”, but the intention was there. Take ear plugs. Tent is also good for a sleep before you drive home (assuming you’re getting yourself there and back) – THIS IS IMPORTANT! You don’t want to survive the race only to die in a car 😉
During the races I always used a corner of the soloists tent – do they have that at Relentless? Don’t plan to stop and sleep – you’ll regret it – so don’t make it easy to stop and sleep. I’ve had other people’s pit crew take pity on me and make me tea.. I must have looked pathetic.
Try and work out what you actually like eating when you’re really really tired and can’t be arsed to prepare anything (and there’s no one to prepare it for you. I ended up with spaghetti hoops and creamed rice (not together) as my reliable food source. Bacon butties are great for a morale boost – there’s bound to be a van dishing those out.