In reply to climb the peak:
When are you planning to do it? What's the longest distance you've done in a day before?
If you are intending to do it soon, then make sure you take lights and spare batteries so that you do not put yourself under pressure to finish before dark. Take enough clothing for the cold!
It would be better to do your first of this distance when there is more light, especially if you are not experienced at riding in the dark.
It would be a good idea to have done a ride of at least 80 miles before trying a ride of this distance but not absolutely essential. This will allow you to try everything out before the big one.
Try to get a good idea of what food works for you when you are riding; trying out unfamiliar stuff on the day can end in disaster (this goes for clothing and equipment too).
When on the ride, if your intention is purely to complete the distance, try to just enjoy the ride and don't get hung up on whether or not you are on schedule to do a targeted time - take time to take in the views, enjoy a cafe stop etc. You will probably enjoy the ride a lot more this way!
I hope you have fun (but you are also meant to suffer a little on these things
), you'll always remember your first ride of a distance like this. In all probability you'll have great highs and lows and get to the end swearing that you'll never do another, but after a couple of hours or days or weeks you'll be planning the next one.