To commute or not? opinions required

I currently cycle to the train station, get on the train with my bike and get off it 20 miles later and ride to work. the current set up sees me riding about 6 miles a day.
I could however cycle the whole thing as i have done once in the past, but...this would mean a daily cycle of around 50 miles give or take. there isnt really a financial reason for doing it other than I think I would be awesome on our sat morning club rides after about 3 months of doing this, so say around may ish I could be a beast on a bike
If I ride there are 3 routes to choose from. ( these are routes from milton keynes to bedford just to put into context.
Route A. The A422. An undulating single carriageway A road of about 12 miles in length
Route B. The A421 A dual carriageway approx 11 miles long, flat and fast.
Route C. The old A421. A flat single carriageway fairly flat approx 11 miles long.
The extra mileage is made up from getting to said roads through milton keynes and bedford.
My concerns are, getting squashed on either the 422 or the dual (high probability I reckon), wearing myself out, having to leave at 6 instead of half 6 although I leave work at half 4 mon-thurs and 1.15 fridays.
Benefits, health and general awesomeness i guess
Anyone else do this sort of commute? how do you get on? is it worth it? should i bother? opinions in general please.

I know those roads well and would chose the 'old' A421 - you are less likely to die. Theres a few roundabouts to negotiate which is always a headache on a bike.

I am currently commuting between Alconbury and Peterborough - 15.2 miles each way down the 'old' A1

*edit: I have to do it on a bicycle as I dont have a car, cant currently afford a car and if things carry on, will never get a car.

The old road sounds ideal - least traffic but still decent sightlines etc.

Yeah, what i should have said is the to access the old road i have to ride down a potentially dodgy b road that is used as a rat run and i have to cross the dual meaning the lazy bit in me would be tempted to just turn left there and take a chance.
I dont know what to do lol.
I too have given up my car, lgf, as I have no intentions of spending 3k a year on a shit box that rots away on my driveway (much rather spend it on bikes that rot away in my shed)

I'm in fear every day my husband set's out on his bike to work he only travels about 15 miles per day but it still gives me the willies. I don't know any of the routes just choose what seams the safest, that offers least risk and look out for loonies

Health wise its a good not so good idea. Undoubtedly you will become far more healthier but as most of us know and I suspect you also know, two wheels this day is never the danger but how cage drivers view and not see two wheels is.

If your comfortable with the risks then I'm sure you know all the safety equipment needed and the risks involved

you'll make the right choice for yourself bud

I did used to commute the old road when the dual diddnt exist on a motorbike and I commuted in london for 15 years or so on a motorbike and bicycle so Im thinking its going to be more risk management otherwise whats the point, right?

If you're physically capable, do it.
The way that drivers become more aware of cyclists is by being around them more often. If you commute at the same time each day, chances are that most other commuters in cars will quickly get used to the sight of you, day in day out.

Plus, trains are awful. Just the worst. I'd rather set fire to money than give it to a train company.

i say commute. i do a 9mile (18mile round trip) to work most days of the week and not only does it mean the extra biscuits i consume at my desk stay off my waist line, it also means i'm not spending £30-£40 a week on petrol, getting stuck in traffic at the same old junctions, missing all the sea views and being able to stop and chat to mates i bump into on the way home.

in terms of risk, you dont have to cycle on a dual carriage way to put your self in dangers way on the road.
adopt the 'eveyones's an idiot' mindset, wear something flourescent or bright and stick your head on a swivel.
and like N/B says, you'd be surprised how quickly you'd become part of the morning commute pattern for other drivers - even on my bike ride that sees mostly coast, i pass the same vans and commuters at the same time at the same junctions each morning.
i even pass the same attractive lady on her bike most mornings - not that i'm looking of course!

Of the options given, old A421 would be my choice, but having a quick scoot on googlemaps - what's the route out via Cranfield like?