I've not really got much on at work today, or yesterday, so I've invested many hours in building a training plan for Brighton Marathon 2020 AND cycling to Norwich. Based on my training plan (which includes Worthing Half and Lydd 20 Miles - both paid for today, and Hastings Half - which I haven't yet, that can wait until the next payday), I will have run 675 miles at the completion of the Marathon in April and I will have cycled 1,263 miles when I arrive into Norwich on the 10th.
Manchester Marathon is £65 to enter. That's just outrageous. I'm tempted by Llanelli Marathon, also on 5th April - £44. Both come with accomodation costs, but Llanelli is where my Grandma was born, she passed 15 years ago so I've not been back since. It might be a nice one to do - further research required. The logic is it might be better to do a marathon for a sub 3 time before the cycle, rather than trying to do the cycle and then the marathon PB in consecutive weeks. Decisions to be made!
If you think £65 is expensive for a marathon I'd suggest you don't consider entering one in North America!
If you're going for a sub 3, I'd definitely recommend trying it before you cycle to Norwich. You really need that recovery time in the last 2/3 weeks before the marathon.