Wow! I'm surprised at the interest. Its what I grew up with and after the Peaks meet, its a bit of a let down.
Let me think on a time that doesnt clash. It really is only Wednesdays and Sundays as I cant take the time off being self employed...
Route 2 is the epic all dayer. You will be knackered but you will see some of the best river meadows in the area no matter what time of year. Winter waterproof stuff is recommended for the lower part of your body as some of the route can be under water (not yet this year). You will need a reliable light weight XC bike that you are happy to chuck over styles and
ride on the main roads as unfortunately there is quite a bit of road work. I used the NF pictured above during a dry April. Bring plenty of the fiddly spares such as chain links, cables and replacement bolts as, unlike the Peaks, as its a commuter belt, it can be a very empty place with no shops/ back-up - a bit over dramatic but its true, you are bloody miles from anywhere in some spots.
Grafham Water is just a quick blast and is best done twice, clockwise then anti clockwise if you wish. It can be ridden to from my house if you are up for it but there is a big Pay & Display carpark. Any bike will do as long as you are happy riding it fast. I prefer drops...
Let me know what you fancy and I'll see what I can foul up organising.